Open an asset in the Lytho asset manager, click show more and edit the asset (by clicking the pencil icon). Open the permissions tab and start typing to search for the permissions you are willing to apply.
Before adding permissions to an asset you have to make sure that the permissions are added in the Lytho settings. Now, open an asset in the asset manager and click all details. Open the Protection tab and select apply permissions to activate an input field for permissions. Here you can start typing to search for the permissions you created earlier in the Lytho settings.
The permissions added to this specific asset now only allow individual users or users in a user group with this permission to view the asset. For instance: 'User 1' is in permission group 'A'. This user can only see an asset with permission 'Lytho' when this permission is added to group 'A'.
In user group management, it is possible to add auto-applied permissions to a group. What this does is add permission automatically to newly uploaded assets or newly created public publications. This will save the user a lot of time adding permissions to new assets and publications.