Welcome to R2R!
A 30 is plenty for clowns, coral, and say a bubble nem...in time. Don't be confused, read threads here, ask questions, and begin the journey! Amazing people here will help you along the way, and if you have the patience to follow and learn you can and will have a amazing tank. You don't have to have the latest and greatest gadgets, but a few simple tools will make your journey more enjoyable.
Don't use tap water! Either spend the money on distilled water or get a ro/di. You could get it from the lfs, but who knows their water quality. Water is the number one in this hobby. Keep your water clean goes a long way. 30 doesn't "need" a sump and you could go hand on back (HOB) skimmer or power filter.
Let your tank cycle! Don't add water, rock, sand, and fish all in one day. There are products in a bottle to help speed the cycle, but I prefer the old way of shrimp and letting the ammonia do its job. You can search and decide the best course for yourself.
Once cycled tank it slow! Every time you add a new fish or coral you change the system. Either by adding more bio load from fish or new supplement uptake from corals. Adding to many to quick puts a strain on your parameters.
ABOVE ALL QUARANTINE! Quarantine everything. Nothing like having your awesome tank and watching it die off because you rushed putting a fish or coral in. A small 10 gallon will be sufficient for most things.
Good luck and ask away, we are all here to help!