mason bee help and tips needed

I am basically a noob but i have decided I want to house mason bees this spring so I have build a house that is a foot tall 5 1/2 inches deep and 5 inches wide. It has a little storage area up top and has a roof that sticks out 2 or so inches. I have also got tubes that have a 5/16 inch opening. I plan on making them different lengths and adding sticks and other stuff so it doesn't just look flat. I don't know if that matters really but why not do it lol. I have placed it 5 feet above my garden bed that has flowers that come back every year. the problem area is I don't know whether to buy cocoons or not. I've read sites that say yes and sites that say no. I never really intended to buy them cause I like starting off small with a few and working my way up over the years but who knows I might have to find a source to kick start or if anyone has any extras. anyway thank you for reading this any tips or help is appreciated a lot.

Hi Andrew and welcome!

Providing houses and habitat for mason bees / wild bees is a big thing here in Germany, it is a popular project for schoolchildren.
You get lots of websites to build your own if you don't want to buy prefabricated ones, and there are a few things to consider. I guess you already looked into this (which kind of wood or bricks, how to drill, how to protect against weather / birds that might use your bee hotel as a free buffet etc.).

But here I have never heard about buying cocoons (not sure where you are located?). If you provide the habitat the bees should volunteer. It might take a little patience but I am sure that the right species will get attracted.
Keep us updated and good luck!

 When I started my first house I just put all the reeds and canes in there and it filled to capacity in a couple months. I never knew we had so many until I started watching them fill their nest tubes.
Now I need to add more nest sites every year because the offspring stick around the following year.  They do a wonderful job as nearly every flower on the property gets pollinated.
 I would maybe get some smaller tubes as well though, they seem to fill up the small 6mm holes first, but I have all sizes and they do use them. When it is dry, do keep some water nearby.

Thank you guys I always see bees around especially around the honey suckles never knew what type. I’ll probably get smaller tubes just to have a variety of sizes. The first year I’ll see if any move in hopefully they do. I made a pretty good size hole right outside the garden cause our natural soil here is clay like. I should of probably mentioned that I live in south eastern Kansas.