How do I run?

[Bob the Beholder]

Yeah, like he said, no running in D1. But, give it a bit of time. The stays in town can get lengthy, but it can really be a good thing in combat. Because, of course, the monsters are as slow as you are. Or slower. Once you start getting better with it, you can react directly to each monster's movements and attacks to position yourself properly, instead of just running around like a chicken with its head cut off, spamming the biggest damage spell you can find, ala DII.