Create docs for self-serve portal links for nextjs-sdk

Author: Alexis

src/content/docs/developer-tools/sdks/backend/nextjs-sdk.mdx

@@ -1606,6 +1606,54 @@ import {LoginLink, RegisterLink} from "@kinde-oss/kinde-auth-nextjs/components";
 
 If the `orgCode` is not specified and the user belongs to multiple organizations, they will be prompted to choose which organization to sign in to during the login or register flow.
 
+## Self Serve Portal
+
+To allow your users to be sent to the kinde portal, you can use the `PortalLink` component.
+
+```jsx
+import {PortalLink} from "@kinde-oss/kinde-auth-nextjs/components";
+
+<PortalLink></PortalLink>
+```
+
+### children
+
+When setting up your portal link, `children=""` must be set, as that will be what your link is called.
+
+
+```jsx
+import {PortalLink} from "@kinde-oss/kinde-auth-nextjs/components";
+
+<PortalLink children="Portal Link Name"></PortalLink>
+```
+### subNav
+
+The  `subNav=""` property allows you to set the area of the portal you want the user to land on. By default, it will send users to their profile. 
+
+```jsx
+import {PortalLink} from "@kinde-oss/kinde-auth-nextjs/components";
+/**
+ * Valid subNav values are: 
+ * profile
+ * organization_details 
+ * organization_payment_details
+ * organization_plan_selection 
+ * payment_details 
+ * plan_details 
+ * plan_selection
+*/
+<PortalLink subNav="organization_payment_details"></PortalLink>
+```
+
+### returnUrl
+The `returnUrl` property is the URL to redirect the user to after they have completed their actions in the portal. The url must be an absolute url to work correctly. 
+
+```jsx
+import {PortalLink} from "@kinde-oss/kinde-auth-nextjs/components";
+
+<PortalLink returnUrl="http://yourdomain.example"></PortalLink>
+```
+
 ## Analytics
 
 ### UTM tags