First, if you do not have Developer installed, you will need to install it. So go into Studio > Apps Market > Search and search for Developer. 

After it is installed, go into the Developer app and you will see the Update Channel there. 

Mine already says Beta but if yours does not, click and change it to Beta.

IMPORTANT: This is still in Beta and will have bugs/issues as you are seeing posted in the discussions. You can choose to wait until the Stable version is released.