How do you stream music form iTunes 12.2?

Hello twozerofour,
To make sure we are on the same page, you have already signed up for Apple Music and want to listen to it on your computer with iTunes. You do not see the option the tabs for "For You" to get content. Let's see if we can get this sorted out.
It sounds like you need to enable Apple Music from the iTunes Preferences window. Take a look at the step that I have quoted below to enable that in iTunes.
Manage your Apple Music membership
https://support.apple.com/en-us/HT204939

On your Mac or PC:

1. Open iTunes.
2. Mac: From the menu bar at the top of your computer screen, choose iTunes > Preferences.
   Windows: Press and hold the Control and B keys on your keyboard to turn on the iTunes menu bar. Choose iTunes > Preferences.
   Learn more about menus in iTunes for Windows.
3. Click the box next to Show Apple Music to turn it on, and then click OK.

After you have followed these steps, you should be able to see the "For You" tab and then be able to add that music to your library. If you are unfamiliar on how to do that, I would glance over this next article for adding music to your library.
Add music from the Apple Music catalog to your library
https://support.apple.com/en-us/HT204839
Take care and let me know if you get this sorted out.

Hey twozerofour,
Glad to hear that toggling that on and off worked for you and you are back to listening to music again.
Take care