Halo 5: Forge released today, so make sure you have the Windows 10 Anniversary Update if you want to join.
Like many, I was ecstatic to hear that it released today, and it came as a very pleasant surprise, because it was the one day I decided to check up on it. Anyways, also like many, for me the link at the bottom of the announcement article did not work, since the windows store reported the game as unavailable at this time.
I am currently downloading the Windows 10 Anniversary update, and I will update this post with personal experience once I am finished.
*UPDATE* The Windows 10 Anniversary Update worked for me! Currently downloading! Make sure you change your app install location if your local drive is running low on space!
There currently is no server browser in the game, but I hear that friends can invite each other for custom games. I will be trying to get more Yume Yumiko members to get on it, so hopefully we can host games for people to join in on.
Hope to see you guys online sometime!