I've been building them for my own department for a while. There is one guy from logistics that does the trash who builds as well. Older guy, pretty knowledgeable. He taught me, and he gets specific bike shifts to build, but I supplement it and just build once a week for a few hours. Get maybe 10 bikes out plus what he gets done. He'll get 20 or so out per shift. We sell a LOT of bikes. Like... I think we lead our district. There's a ton of new long bike trails around our area. You can do easily find over 100 miles of trail riding if you can stand being on a bike that long, heh.
It's not too hard once you get it down, just takes common sense. Make sure things are tightened properly, not on backwards, make sure tires are over 50 psi, etc. Brakes are the only thing that's a little annoying to adjust, as almost every front brake is going to come messed up from he factory. But it just takes a bit of experience to get it done right.
The worst are those stupid orange kids Mongoose bikes with the little plates that squeeze together within the braking system. Giant pain in the ass to fix or adjust. They have two cables going to the brake. I mean.... why? Same with the little green and black Razor bikes. Terrible brakes. We don't build the things unless there's nothing else to do. It's a shitty product that's going to break and get a kid hurt. Hopefully the bad sales will reflect that and they'll pull them.... >.>
Building on the floor though? Good god no. Where the hell should we do it? I need the stand, a table for my tools, a place to put the boxes I'm tossing my trash in... it'll take too much space from a main aisle.