Probably need to find out if they use e-targets, or if you have to go pull targets in the pits.
If the former, find out if they provide tablets or if you need to bring your own (just needs to be able to connect to WiFi and open a web browser).
If the latter, bring a hat, water and snacks, as you may end up being down there for a couple hours (depending on the pit rotation). Definitely take ear and eye pro with you to the pits. First time I went down, nobody told me
Bring extra ammo, as mentioned above. If the match program course of fire calls for three strings of 2 sighters and 20 record shots, don't bring exactly 66 rounds. Bring at least 70, 75 would be better. Things happen - round that doesn't go off, someone miscounted how many rounds you shot and you need to fire another one, or several other technicalities that involve you needing to fire one or more extra shots. You can always take 'em home and use them another day
Tenth mil clicks will work... you'll most likely have to hold off a bit to get your group centered up. Not a big deal, just something to be aware of so you don't cause yourself grief trying to click back and forth with 0.36 moa clicks
If you have a spotting scope or binos, bring them - particularly if the match has pits and you have to pull targets. There's not always enough room on the line for you to lay alongside the other people (relay) that are shooting when it's your turn to score for them. A lightweight folding chair is probably a good idea as well.
A lot of this stuff, if you don't have it, just let the match director (or your friend) know, and they'll get you squared away. Most people don't have any problem sharing their gear with new shooters.
Just be careful with borrowed gear... I lost count of how many times I let people borrow my spotting scope, and they left it 'up' when they got up from the chair after scoring - and the wind promptly caught it and dumped it into the gravel, right on the front lens.