Paocai Fermentation Jar

I've recently received a paocai jar as a gift. I am an avid pickler, but I usually only make fridge pickles or canned pickles.

I have had many pickled Chinese vegetables but I've never pickled them myself. Online says not to use water heavy vegetables, like cucumber, but thats usually what I make pickles with? Right now I have radish, carrot, onion, and garlic. Do you have suggestions on what else to include and maintenance? The forever pickle brine is new to me as well.