Trying to do a purchase ledger but cant seem to do it?

i am trying to do and set up a purchase ledger and i want and need to keep track of the rent as the council like charging me more than they should. could any one please help. i am really finding this system harder than it looks. i have put what i need in including invoices and what people have been buying but still cant seem to figure this bit out.

Your request is vague, @brighter. To help you, people will need more specifics. I suggest making sure you have read a few guides first, then ask detailed questions. Start with these: