This advice is a little late but most online retailers will assemble your gear free of charge if you ask. If you do it yourself just remember you only need a little "hug" on the hoses, anything more than a small open end wrench is too much tool.
If you own a tank give the regs. a test breath, if not it’s probably worth a couple dollars to rent own before you take the new rig out diving (or NOT diving). Just make sure to follow the directions for connecting the HP (high pressure) and LP (low pressure) ports and save the port screws. The firt stage is marked LP/HP