My Marin Stinson has 48-38-28 chainwheels and 14-28 rear cassette with 7 speeds.

What do these numbers actually mean, at the simplest level? How do they relate to how a bike feels and handles, for hills/speed etc? If I was curious about a bike with better hill climbing over short steep sections then what numbers would I need to be looking at (or do I just need to pedal harder?)

Please feel free to link me up to anything that will help Sheldon is a little beyond my current understanding however . Thank you.