When laying track, I always position the turnouts first. I don’t glue them down, but pin them in place with either pushpins or t-pins. Once in place, I connect sections of flextrack to the turnout, then trace the outline. Once that is done, I spread a thin layer of caulk as mentioned above, connect with flextrack with rail joiners, then press it into place into the caulk. Place weights on top of the track. The caulk will be dry and the track secure usually in less than an hour. If you need to move the track, slide a putty knife under it, and it comes up fairly easily.