diff --git a/appinfo/info.xml b/appinfo/info.xml
index 8177160..6e4aa44 100644
--- a/appinfo/info.xml
+++ b/appinfo/info.xml
@@ -16,6 +16,6 @@
         <database>pgsql</database>
         <database>sqlite</database>
         <database>mysql</database>
-        <nextcloud min-version="29" max-version="29"/>
+        <nextcloud min-version="29" max-version="30"/>
     </dependencies>
 </info>
\ No newline at end of file
diff --git a/lib/Model/Organization.php b/lib/Model/Organization.php
new file mode 100644
index 0000000..56729eb
--- /dev/null
+++ b/lib/Model/Organization.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace OCA\OrganizationFolders\Model;
+
+class Organization implements \JsonSerializable {
+    public function __construct(
+		private int $id,
+        private string $membersGroup,
+	) {
+    }
+
+    public function getId(): int {
+		return $this->id;
+	}
+
+    public function getMembersGroup(): string {
+		return $this->membersGroup;
+	}
+}
\ No newline at end of file
diff --git a/lib/Model/OrganizationRole.php b/lib/Model/OrganizationRole.php
new file mode 100644
index 0000000..3358bfb
--- /dev/null
+++ b/lib/Model/OrganizationRole.php
@@ -0,0 +1,29 @@
+<?php
+
+namespace OCA\OrganizationFolders\Model;
+
+class OrganizationRole implements \JsonSerializable {
+    public function __construct(
+		private int $id,
+        private int $organizationId,
+        private string $friendlyName,
+        private string $membersGroup,
+	) {
+    }
+
+    public function getId(): int {
+		return $this->id;
+	}
+
+    public function getOrganizationId(): int {
+        return $this->organizationId;
+    }
+
+    public function getFriendlyName(): string {
+		return $this->friendlyName;
+	}
+
+    public function getMembersGroup(): string {
+		return $this->membersGroup;
+	}
+}
\ No newline at end of file
diff --git a/lib/OrganisationProvider/OrganisationProvider.php b/lib/OrganisationProvider/OrganisationProvider.php
deleted file mode 100644
index f94726e..0000000
--- a/lib/OrganisationProvider/OrganisationProvider.php
+++ /dev/null
@@ -1,15 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace OCA\OrganizationFolders\OrganizationProvider;
-
-abstract class OrganizationProvider {
-	protected $id;
-
-	public function getId() {
-		return $this->id;
-	}
-
-	// TODO: functions to access organisation structure
-}
\ No newline at end of file
diff --git a/lib/OrganisationProvider/OrganizationProvider.php b/lib/OrganisationProvider/OrganizationProvider.php
new file mode 100644
index 0000000..9266a84
--- /dev/null
+++ b/lib/OrganisationProvider/OrganizationProvider.php
@@ -0,0 +1,72 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\OrganizationFolders\OrganizationProvider;
+
+use OCA\OrganizationFolders\Model\Organization;
+use OCA\OrganizationFolders\Model\OrganizationRole;
+
+abstract class OrganizationProvider {
+	protected $id;
+
+	public function getId() {
+		return $this->id;
+	}
+
+   /**
+    * Get specific role by its id (unique within OrganizationProvider)
+    * @return Organization
+    */
+	abstract public function getOrganization(int $id): Organization;
+
+   /**
+	 * Return one level of the Organization Tree
+    *
+    *        ┌────────────────────────────┐                                           
+    *        │         Root Node          │                                           
+    *        │ (of Organization Provider) │                                           
+    *        └──┬──────────────────────┬──┘                                           
+    *           │                      │                                              
+    *           │                      │                                              
+    * ┌── ── ── │── ── ── ── ── ── ── ─│─ ── ── ─┐                                    
+    *           │                      │                                              
+    * │         ▼                      ▼         │                                    
+    *    ┌──────────────┐      ┌──────────────┐                                       
+    * │  │              │      │              │  │                                    
+    *    │Organization 1│      │Organization 2│    ◄── ── ── getSubOrganizations();      
+    * │  │              │      │              │  │                                    
+    *    └┬────────────┬┘      └┬────────────┬┘                                       
+    * │   │            │        │            │   │                                    
+    *     │            │        │            │                                        
+    * └── ├─ ── ── ── ─┤ ── ── ─┼ ── ── ── ──│── ┘                                    
+    *     │            │        │            │                                        
+    *     ▼            ▼        │            │                                        
+    *    ...          ...       ▼            ▼                                        
+    *                 ┌── ── ── ── ── ── ── ── ── ── ─┐                               
+    *                   ┌────────────┐ ┌────────────┐                                 
+    *                 │ │            │ │            │ │                               
+    *                   │ Suborg. 21 │ │ Suborg. 22 │   ◄── ── ── getSubOrganizations(2);
+    *                 │ │            │ │            │ │                               
+    *                   └────────────┘ └────────────┘                                 
+    *                 └── ── ── ── ── ── ── ── ── ── ─┘                               
+    *
+    * @return Organization[]
+    */
+	abstract public function getSubOrganizations(?int $parentOrganizationId): array;
+
+   /**
+    * Get specific role by its id (unique within OrganizationProvider)
+    *
+    * @return OrganizationRole
+    */
+    abstract public function getRole(int $id): OrganizationRole;
+
+   /**
+    * Get all roles of a specific organization
+    * 
+    * @return OrganizationRole[]
+    */
+	abstract public function getRolesOfOrganization(int $organizationId): array;
+
+}
\ No newline at end of file
diff --git a/lib/OrganisationProvider/OrganisationProviderManager.php b/lib/OrganisationProvider/OrganizationProviderManager.php
similarity index 100%
rename from lib/OrganisationProvider/OrganisationProviderManager.php
rename to lib/OrganisationProvider/OrganizationProviderManager.php