pH should be 8.0 - 8.2 and temp 25 - 26 degrees IMO.
I would get coral first personally. I would be introducing a hardy soft coral first and then leave it atleast a week, then another coral. Then I would get a fish and preferably just the one, you can always make a pair of clowns later! This size tank 3 fish is going to be really pushing the limits. Especially if you are new to marine fish keeping, you are going to need to do religious weekly water changes and keep a very, VERY close eye on your parameters as a "little" ammonia spike in 38L of water can be brutal!
As for coral, I would be adding a hardy morph or zoa species first then a torch as they are quite hardy also. If in 2 weeks the corals are expanding nicely and havent lost colour and your parameters are all in check I would think about adding a fish. Stocking a small tank like this should be a process over about 4 - 5 months IMO.