[Zeke]

AC only so you need to buy AC rod. There are a few choices, but for down and dirty (really, a little rust and paint) get some 6011 or 6013. They are mean and nasty rods that penetrate while trying to stick all the time. It takes getting used to.

For building up on clean work you can use 7018 but since that needs to be newish and kept warm, I don't use much 7018. It's an industry standard for a cap pass or 3. Runs nice.

If you get some 7028, that is the AC equivalent of 7024 "jet rod" a high deposition shallow weld that runs like butter and makes you look better than you are. Easy to start and run, you can almost just drag it in the weld and it welds all by itself, no manipulation required. With good clean prep it can be strong. Flat welding position only but I doubt you are going to do much overhead welding with that machine. The others I mentioned are all position.

If you learn to lay down a decent bead using 6011 with a Lincoln Tombstone, you can weld just about anything anywhere. Try not to overshoot the amps. Yes, it makes it easier to light up an arc, but too hot will get you in trouble soon enough. Dial it back a bit and be smooth. 75 and 90 is about all you'll ever need unless you need to build your own steel bridge.