How to create a pattern with Illustrator
First, create your own pattern like below, and select with direct selection tool.
Go to Object---> Pattern---> Make.
You can adjust the location, space and edit your pattern shape.
After that, you have to click the 'Done' on the top of banner.
Go to Swatches palette and click the pattern.
And select the rectangle tool for checking your pattern.
Here is your pattern sheet!
Myungja Anna Koh