How do you create a will

I am the only living parent and I wanted to know how do I have someone else added as a legal guardian in case of my death how do you create a will.

What other things do I need to know I feel like no one teaches these adult things it's like you have to have this as soon as you have a child. What have you guys done and how do you ask someone hey if something happens will you take care of my child so you have to get there signature