Install Fluorescent Tube Light, Correct way to Rotate?
I have replaced tubes on easily 20 different kinds of fixtures with a wide variety of tombstones (that's the lamp socket the tubes go into).   It's a dog's breakfast.

Many of them rotate 90 degrees.  Some have channels or cages that require exact 90 degree rotation.
Some of them only allow about 60 degree rotation.
Some of them pull straight out/down, although 60 degrees of rotation will likely make one end pop out.

The upshot is you really have to &quot;go by feel&quot; - remember you are holding onto a glass thing, force hard enough but not too hard.
For what it's worth, the tube ends will have a &quot;dimple&quot; perpendicular to the pins, so when it's square into the socket, the dimple is lined up with the socket.
Once the first tube is out, stop and take a close look at the tombstone, and see how it is designed to work.
Unfortunately I'm not at my site, so I can't give you a rogue's gallery of different tombstone pin paths. Suffice it to say, there are many.

Most LED tubes are aligned so the light shoots out the way the tombstones come out.  If you want to get rid of the infamous LED eyeball-burning glare, at the expense of less light, install them &quot;upside down&quot;.