Some sump help

Hey there, I'd like to know how to set up my sump properly.

I have a 500 litre tank and am using my old 30 litre tank as a sump in the mean time until i can get something bigger. Any advice on how to equip it would be appreciated.

The pic attached is what my sump looks like, inlet in chamber 1, gravel and finer sand in chamber 2 and outlet in chamber 3.

I do use filter floss and activeted carbon but for this threas i'd like it if you thought of my sump as being empty and being set up from scratch.