You can cook pizza directly on the tray. With the slope at the front, it's possible to put it in and take it out with a pizza peel. The other way round it's much harder. This way you can preheat the tray and don't have to take it out to load your pizza onto it
I prefer a stone, but this worked well when I was between pizza stones
It doesn't really matter most of the time, but the sloped side should be the one facing you. Any rack designed to go inside the tray would better align with any grill (broiler) elements in that position. It also makes access easier if you don't have any rack in it & need to reach into the tray itself.
The holes may be for some additional attachment, or ...
Increase your oil and Make sure you have enough flour, your dough should make a kissing sound when you take your hand away from the side. Try baking at 400 degrees F for 30 minutes. Put the rack so your loaves are right in the middle of your oven. This works for me. Hope it turns out for you too.