Yeah I was thinking about making a mini wall but but Im clueless on what to use and where to start. and what to use.

Ive decided to use a product called Megazorb to line the tray base, Its supposed to be similar to Carefresh (Which Ill be using to put in their little home as bedding) and Ive found the Megazorb real cheap at 10 pounds for 75 litres !!!