The best thing about dips is that they’re easily scaled to how strong you are. If you’re in peak shape and already relatively strong, then you can do them with your hands on a chair and feet propped up on something in front of you, so you’re using more of your bodyweight. Or you can get crazy and do them suspended between two bars.
If you’re not quite to that level yet, that’s entirely OK. Just keep your feet on the floor, prop your arms up behind you, and focus on keeping your elbows as close as possible to you throughout the movement. You’ll start seeing improvements in no time.
When it comes to building serious biceps there's probably not a better movement than chin-ups. They’re a great movement for hitting nearly the entire body, but especially the biceps, thanks to doing the movement with your palms facing you.