W2A

Great customer service. Had an issue with the throttle handle, was going to return the bike but their customer support team contacted me and sent me a replacement.

First thing, remove as little packaging as possible so you can access the battery and the area where the battery attaches. Get that battery charged up somewhat, plug it in and twist the throttle. If the back wheel spins and you get no error codes, continue with assembly.
The instructions say to put the kickstand on first; meh. I would attach the handlebars first, which allows you to flip the bike upside down and continue assembly in that position. Almost everything you need to install can be done upside down, including the kickstand. The only things you need the bike rightside up for are the one or two things that attach to the handlebars.
I don't know about range, but we rode around for about 2 hrs and didn't put a dent in the battery life. Power is great, cruise control is great. I do recommend this bike, especially for the price.