Most of us learn how to weave as children, even if we are not weaving yarn, just a simple paper place mat. The same concept translates to yarn.
When I was young, I loved weaving, so I learned the process for weaving a pouch on a cardboard loom, and I found a book that described how to make a fork loom. Now I have moved on to bigger things!
I learned to weave on a floor loom in 2004 through a class with Gwen Handler at Common Ground on the Hill.
The weaving looms I've used have become bigger and more complex as I learned more and got older. As a child, I used cardboard and a backstrap rigid heddle loom made of plastic forks. Now I have a 4 harness Baby Wolf floor loom.
The easiest way to start is with some yarn and a fork. Start going over and under through the fork tines. When you get to the edge, wrap around and go over and under again. This time they will be the opposite way on the fork so you can see the weaving pattern.
If you want to make a flower, put a piece of yarn in the middle of the fork at the bottom, weave, and tie it around the woven rows. The little rose can fit on a bobby pin for a simple hair decoration.
If you really like this way of weaving yarn, make 4 long strands twice as long as what you need for a belt. Weave around them just like the fork and push it all together to make a belt!