25 litre set up.

[Canary bird]

Hi I have 3 tanks set up and fully established, my 25 litre I was using for a fry, but I've decided I fancy keeping red cherry shrimp, if I can get them here ! So can someone just run through the basic set up and what I need ..
I already have a sponge internal filter, pfs substrate , what else ?
Something else for my husband to roll his eyes at
Thanks in advance

Suzanne