Hi there!
I was just like you. The only surgery I had prior to my LIS was my wisdom teeth removal.
Personally it might be better if I DON'T share my LIS experience with you, because it didn't go well.
That's not the case for a lot - if not most - people, so no need to scare you too much.
I just had to use some Fleets enemas recently, and that also didn't go smoothly. I used one and it didn't work, and when I tried to use the second one it was just too painful, and I had to call my surgeon and tell her it was a no go. Thankfully it wasn't a problem. I did have a small BM about 12 or so hours after using the enema, but yeah...didn't really work. The nurse I talked to said that happens to some people. If it does, don't panic like I did, just call your doctor/surgeon as soon as possible and ask for advice.
I don't know if they're making you stay away from high fiber foods before your surgery, but stick to soft foods for a few days beforehand. Jello, yogurt, bananas, soup... Afterward you'll be doing the same thing, of course. Be sure to have ice packs on hand as well, since there will be swelling. Sometimes the swelling can prevent you from urinating - that's what happened to me when I woke up. In that case you'll probably have a catheter put in for 2 days.
I didn't take any of the hardcore pain killers they gave me, since those make me sick. They also had me take a laxative afterward - Senokot, I believe, which was a HUUUGE mistake. Gave me the worst nausea and cramping I've ever had in my entire life. Had to call the surgeon at 3 in the morning and beg him to call in some anti-nausea pills, which didn't work. If you know of a laxative that works well for you personally, I suggest asking if you can use it instead of the one they (might) give you! Having nausea on top of the pain is no fun at all.
And of course, try not to sit too much after your surgery!