Use Lawnfix MS Polymer. It's green coloured & comes in 290ml tubes, there is also a 300mm wide jointing tape for use when it's over soil or other difficult surfaces.
Staple or screw it down for easy removal later no need to glue it's overkill Sent from my HTC One M9 using Tapatalk
I would just spray glue or tackifier and fix with a few screws around perimeter. Laying loose over sharp sand and screwing to a timber perimeter is the method of installation outside (and recommended method as per manufacturers) if floor is pretty flat you would probably be fine without any adhesive unless you have joins to do ofcourse in which case you can use tape and green adhesive from decent suppliers. done some outside in the summer
