Bamboo can be floated, glued or nailed. My company (Fair Pacific Bamboo Flooring) floats bamboo in about 1/4 of our installations with no problems.
If you have standard tongue and groove planks, you would use a traditional floating method (glueing tongue to groove) with any of the variety of good floating floor adhesives on the market.
Unfortunately, what you are seeing with your planks not fitting is common with low cost planks. The milling and/or drying is not what it should be, so you end up with planks that have large gaps. Sometimes, this can be mitigated by applying pressure to the planks to bring them together while nailing or while the adhesive sets.
As far as acclimitization, up to 72 hours is recommended. That may help your situation somewhat.
Finally, if putting down over concrete, you will likely have too much moisture in the concrete for a satisfactory wood flooring installation. So you must provide a moisture barrier. Typically, this is 6 or 8 mil polyethylene sheeting, taped at the the seams and along the edges. The floor is then floated over the top. Bostik has a nice product called MVP that is a "paint-on" moisture barrier. You basically roll it on and it forms a moisture-proof membrane. You can then float your floor over it, or even glue it directly to the membrane.
I hope this helps! There is way to much bad bamboo flooring on the market - Fair Pacific is here to help correct that situation, because quality bamboo flooring planks make a very nice, very sturdy, environmentally friendly floor.
-Greg Pasquariello