Handy items: tape measure, pencil or chalk, and a spirit level.
Here are some options of how to hang your works:
The old hammer and nail. If you know where a stud is located in your wall (and just to be clear, a stud in this context is a strong piece of timber in the wall to which plasterboard is attached, not a fine looking fella). It can be located with a stud-finder (and that’s an actual tool, not another word for tinder), and it just so happens to be located in a pleasing place, hammer in a old strong nail and hang away.
Anchor screws are good to use if you can’t find the stud to pop a nail in (gosh, this sentence could really be misconstrued). Make sure you buy the right strength for the weight of your frame. You’ll need to drill a hole, and then gently tap the anchor in and screw in the screw, leaving just enough sticking out to hang your frame on - either by the hanger on the back of the frame of by looping the wire over it.
Picture rail. A lot of beautiful old Victorian style homes already conveniently have these, but fear not, modern home dwellers - you can get them put in (or even DIY). Picture rails are brilliant, as you can hang frames from any height, and swap or arrange them around as you wish. A commitment phobic’s best pal.
If you’re unsure, definitely consider getting some help - you don’t want to end up with cracked tiles, holes, burst water pipes, or broken picture frames. Google or gumtree will help you find someone who does this professionally, and will save you a potential giant headache.