We suggest you watch the videos first so you can really see what you're doing - but here are some written instructions too:
Turn the handlebars until they're dead straight and centred over the front fork. Tighten up the bolt with the tool we've included in the box.
Fit the saddle on the seat post and tighten up with the tools we've included, making sure it's at the right height and angle for your riding style.
Pop the front wheel back into the front forks, tighten up with the tools included (even easier if it's got a quick release skewer).
Pop the rear wheel into the rear triangle, tighten up with the tools included (even easier if it's got a quick release skewer) Whilst taking care not to damage/bend rear mech.
Make sure both front and rear brakes are working.
Thread the pedals back onto the crank arms. They screw in the opposite way to everyday screws, which means they'll only get tighter as you ride.
If the bike has a front mudguard, we've had to remove that too (our courier is very particular!). It simply screws back onto the front fork, secured at the top by the bolt that also attaches the brakes to the bike.