There are two main ways of creating an album in the mobile app:
1. Create an album from Albums
Open the mobile app
Go to Go to "Photos" in the main menu
Go to "Albums" in the bottom right corner of the screen
Click the plus icon
Select the photos you want in your album from your timeline by tapping them
Tap the check mark in the top right corner
Name you album and tap "Save"
2. Create an album from your Timeline
Open the mobile app
Go to "Photos" in the main menu
Tap the 3 dots in the top right corner and choose "Select photos"
Select the photos you want in your album by tapping them
Tap the album symbol in the bottom menu
Tap the pluss sign in the top right corner to add a new album
Name you album and tap "Save"