You do not need everything at once. Start with the essentials in bold, then fill in as you go. Tick things off as you buy them.
Kitchen
Bedroom
Bathroom
Living room
The boring essentials
Save money
Local buy-and-sell groups, charity furniture shops and end-of-line sales at the big retailers can furnish a flat for a few hundred pounds. Buy the mattress and sofa new; almost everything else can be second hand.