First off, nail down what you're hoping to achieve. Just a vague feeling that you want to start working out isn't very motivating. Set yourself some kind of target, write it down, and it'll help focus you on the things you're doing. It doesn't actually matter much what kind of goal it is, just so long as you have one.
And then start a routine at as easy a weight as you can. Sticking to working out and making progress is a long term business. It's worth spending the first couple of weeks just getting used to finding and spending time moving weights without it being tiring or painful. After that the details depend on the routine, but if you add a little weight, or do an extra rep, then you're making progress. If you rush, start missing reps, burn out, get injured or just quit - you're not making progress.
Commit to something long enough and you'll see the improvement.