Just attempted my first Labyrinth (the one at Lv 33). I cleared a room, went to next room with boss in it, I got the boss' health to like half or something before he exited the room.

Then I continued, cleared the room, went on to next room, it seemed to be the same as the first room I cleared...

Then I noticed I wasn't getting any xp or drops anymore...

I'm lost...

I tried googling some guides but all seem to be about how to beat the boss. Not helpful. How the heck do I beat the labyrinth? Like, not run the same rooms over and over, getting no xp or drops?

Wasted like 2 hours in here before I gave up and quit.

poelab has all 4 layouts and updates daily.

almost every instance exit has an altar with a map layout when you click it

there's 3 fights to kill the boss completely

go from left to right on said map

you fight him 3 times, and rooms look pretty similar there's only 3-4 styles of room but the layouts change

The intention of the lab is to finish it and gather 2 ascendancy points.
loot and xp are by-products.
4 labs x 2 point to enhance youre char.
The daily lay outs can be found on the site poe lab.
For explanation go to the poe wiki.

Most consider labs as an unwanted "have to do" to get the points.
And ofcourse there are labrunners as well.
Keywords to do them well are life regeneration and bleed protection.