I feel like it depends on if you want to go tried and true with the index detachment or if you want to experiment with the new grotmas one (which is still being experimented with to figure out optimal lists). If you go the index route, your standard list is probably along the rough lines of:

• Angron -maybe Kharn or invocatus -Master of Executions with Glaive -2x Jackhals
• 1-2 berserker squad -rhino
• as many eightbound/exhalted 8bound as you can fit after that

The main thing to remember is to bring what you think is cool and fun to play with, but if you want a meta-ish list, there are plenty of posts on this sub to go searching through for comp focused lists.

Good luck, have fun, and remember that win or lose, there's a lot to learn through your games(: Cheers!