How should I store datastore values?

If I wanted to have like 3 stats for each player, EXP, level and gold, which way of saving would be best: Putting EXP, level and gold into one table and saving the table all together, or saving each stat separately?

Extra: I want to make a global leaderboard, should I not use normal datastores and just use ordered data store, or how would I use ordered data store to create a leaderboard?

I suggest you store them together. It will also help you not run into datastore limitations on how many times they can be called Example:

["EXP"] = 0,
["Level"] = 0,
["Gold"] = 0,

I'm leaving you off assuming you know how to use datastore properly and instead is asking a question about how to store values.