It was actually a pretty simple process, but it does require thinking ahead because it has to sit and brew for at least a month. Basically, you combine vanilla beans, chopped into approximately 1" pieces, and vodka, and shake daily for at least a month. Ours sat for closer to two months, and the longer it sits, the stronger the flavor becomes.
Then I just set up a little straining system, placing a coffee filter inside a strainer to get out as many little particles as possible.
After it was strained, I used a tiny funnel to fill two dozen 4 ounce bottles.
The fun part for me was making a punny little label.
There are lots of instructions for making vanilla available online, and the vendor I ordered the beans from through Amazon even sent some as well. If you are making your own, I would recommend ordering the beans from Amazon as the prices are a lot better than what you would pay at the grocery store. It was a fun project for us and we even have a little leftover for our own baking.