How to install OS 10.9.0? Only updates seem to be on the support site.

I installed a new SSD drive in my aging MacBook Pro. I a duplicate of the previous 1 tb internal drive, which is in an external housing. I want that system, user and applications on the internal. Migration Assistant wasn't going to do anything when the internal drive was simply formatted.

So, it would seem I need to install 10.9 on the internal drive. It's currently running 10.8.5.