replacing tires and tubes
You just need to match the size.  Bontrager is just a tire that Trek used for that bike.

The size will be on the tire
The bike comes with a 700x35c
The 700 is the rim size - you have to get a tire that size
The 35 is the width of tire - you have some variance there
For your bike might as well just stay with a 700x35c
For a tube you will get a range like 700 x (32 - 45)