This video explains how to do it. If you need weight for casting, you can slide a cone-shaped bullet worm sinker on the line before tying the hook and putting on the worm or soft lure.
Another way to rig soft worms for bass-fishing is the wacky rig.
And these two videos show how to fish the wacky rig Senko. In short, flick it into covered areas (under trees and docks) or cast it into open areas and let it sink to the bottom and reel it up, then flutter down, then reel it up. If you keep getting hung up on the bottom, you can slow reel it in. To garner more bass attention, reel and stagger-jerk it as you bring it in.