Ok...
Let's try basics...
Right click in track view and add a midi track...
select the input as omni if it isn't....
with the focus on that track, touch your key board...
does the level bounce? You won't hear anything yet
because you haven't routed the signal to anything
but the line level should bounce....
After that... it's a matter of routing the output of the track to the software synth of your choice...
On that software synth, make sure you pick a program...
Sometimes I get confused when I add a new synth and can't hear it...
It's possible to route the midi signal to a synth without a loaded program... the result is silence...
So, open the synth and load a program...
Now... when you hit a key... the sound should route to the midi synth and you should hear output....
I usually use "Insert Soft Synth" and follow the directions in the help file...
Insert Soft Synth Tutorial