G'day again mate.
I have no idea where you live but if you live near the coast, get a copy of TRADEABOAT and phone a broker near you.
Be honest and tell him you know nothing, what you are doing and plan to do and ask if you can come in when he is not busy(probably most of the time) and tell him what you want to do and your budget.
Most are sailors or experienced boaters to start with and if he is sensible, he will want to get you on the right track. We all started out the same as you.
(And we still do not know it all.....YET).
A coastal boat is different to one that will take you 200 miles offshore.
One is for a day or two and is light built, the other is for a couple of weeks or so and is a heavier displacement. It will carry more water, food, fuel etc.
He should explain that to you and before you know it, you will know of the few boats that will suit you.
What you want and need might be beyond you right now but don't let it stop you.
It is only money and time. Both are there if you want them.
Good luck and remember, fortune favors the brave.