A decent trainer will ask you what your fitness goals are. Then you say:
"While I've made some decent progress, I'd like to be a lot stronger. For example, I still can't quite do 'real' pushups. It's hard for me to gauge my fitness beyond that. I can deadlift about 80lbs, maybe more, but that's about all the freeweights I've got so I don't know. I'm also not sure, even having watched a lot of videos and whatnot, that I'm doing any of this stuff with good form."
And then the trainer - if he or she is any good - will say "ok, let's have a look at some good warm-ups for weight training, I'll show you the weight room and go over how to use everything, we'll look at some basic lifts and proper form, and set up an initial workout routine for you."
Trainers are supposed to train you in the way you want to be trained. Nobody needs coaching on how to use an elliptical or even a treadmill, really - the trainer will probably be happy to have something to actually DO.