As a fellow 40 gallon newbie(ish), I'll just throw out what I have/like,,, which is all beginner/easy stuff...
Fish:
- Clownfish (of course)
- Bicolor blenny
...next maybe:
- Firefish
- Pajama cardinal
Corals:
- Zoanthids
- Ricordea mushrooms
It's all personal preference and compatibility.
Equipment like lighting first as others mentioned.
Start with fish and make sure you have a handle on parameters/nutrients for a while before corals.