>>>how do I selected a certain area of data (notes) and move them back to a certain position before. Do I use delete to do this?

Edit -> 11. Shift Clock

That function will ask you to define your Target Track and Measure From/To, your status (what data you want to shift), Channel, etc.

>>Furthermore, when I copy a track 1 into track 2, I also get its part of the performance,

Part? What does that mean? From the rest of your question, it seems you mean "channel number."

>> which I don't want but only the notes. So when I play channel 2, it actually plays channel 1 part as well.

Because you didn't changae the channel on the new track.

>>How do I get only the notes but not the part?

You can't. You have to change the channel on the new track after you have copied the data.

Edit ->7 Change MIDI Channel