You'll probably spend an awful lot of time in the first few weeks trapped in box hell, looking at the fabric of the building and thinking "what the heck have we done?" but with the odd satisfied smile. Then slowly it starts to slot into place and before you know it the satisfied smiles overtake the "OMFG" moments.
One tip - label the box with the kettle and emergency booze rations in as "Grandad's ashes" and keep them very very close. Guaranteed no one will touch them!
You'll be fine. Good luck.