distributor installing into fresh 318

hi just got my 318 back from the shop with a total rebuild since I did not have the distributor the guy could not install it for me, so he did not install the drive gear, told me he has the #1 cylinder at top dead center for me (compression), told me to just have the rotor set at # 1 on the the distributor cap and put the gear onto the bottom of the distributor and drop the whole assemble into the block, this may sound dumb but how do you know where the # 1 is on the cap of the distributor?? do you just pick a spot and put the plug wires in the correct firing order?? and which side for the engine should the vaccum advance face passenger/driver side ?? thanks. for any information.