The pen tool is evil!
Not really, it just takes a bit of getting used to.
If you just click the pen tool a few times on the artboard, you create an number of anchors (dots) and each time you click a new anchor – it’s like you’re drawing connect-the-dot style.
If you click back on the original anchor, you’ll create a full ‘shape’.
If you click, hold and drag using the pen tool, you will create handles.
Handles allow you to create curves between the 2 dots/anchors.
You can move the handles up, down, left and right.
If you hold down the ‘alt’ key and click on an anchor point – you can go back through and change the curves you made