Hopefully this is the right forum to post on

For starters I have a 7 speed Trek 7100 WSD.

When going up hill, am I supposed to shift down a gear on the front break (left side gear) It has 3 speeds on the left side. I had a heck of a time today going uphill, and it seemed if I shifted up to 1 .. maybe it's just because I am not used to steep hills and just don't have the momentum.