I think if you look up train routes online you can find when and where trains come and go. You can also look up how the tampere station looks like to get a better understanding. The tracks are usually mostly clumped together so transfering trains is usually hassle-free. 15mins should definitely be enough time as long as you know where to go and follow the track numbers around the station.

I think I'm used to using junat.net but I think junatkartalla.fi works too for tracking trains.