If you download the app for DSB, DB and SBB and look for your train, the information about which platform the train departs from and arrives at will be there. 

Like Anna said via App of the train companies, and you have most of the time also this information on the screen in the trains and in the station. 

Just like DSB does this; listen/look for announce In the train-in DE on DB they will also tell how late you are on arr (always) and how late-or not-the other train will be. Expect some near or total misses.

DB will also often tell: selber bahnsteig gegenüber=same platf other side-this is most often the case for such tight logical connections. In their ICE its always german then (bad ) english