Oh wow...dont be intimidated. You can do it. There are a lot of people here willing to help you figure out what to do first.
Which would be to answer some hard questions
Do you want to keep coral and what kinds, soft, lps(large polyp stony) or sps (small polyp stony).
They all require different lighting.
What do you want to keep for fish? Smaller ones that you could keep in a nano tank, tangs that require much larger tank. There are fish that do great in a 75-100 gal tanks. Then some require much larger tanks and dont do well with some or most coral. Trigger fish for example need a 180+ tank and most will nip at or eat/kill lps coral and clams. I have been lucky with the one I have as far as coral, but he will eat clams.
Just some things to think about.
But really, dont be intimidated by the whole thing. I have learned over the last few years, its not really as hard as it looks or sounds.