Hello I am new in here; Blogger. Please notice, English is not my native language. I hope you can understand what I am trying write down for you!
How to use Pen Tool in Illustrator Software, Take a look on Tool Window, he/she can see many tool in a window. One of icon show a pen, it is pen tool. Click it, then he/she should able see their mouse looks as pen. Once he/she done, click till he/she see a dot on layer, move their mouse and he/she can see a line between dot and mouse. The more he/she add some dot the more he/she will see the line between dots and mouse. Play with it as much as he/she want or need for design. Once he/she done, click on first dot and it will set as layer. He/she can also use it to draw over a picture as their own layer. How to add dot, move mouse over line and he/she should able to see "+", it will add dot in a layer. How to delete dot, move mouse over line and he/she will see "-", it will delete dot from layer.
That is all I can remember, I hope you can understand what I am trying to say!