welcome back into the hobby!!! and welcome to this site!!! you will find any answers you are looking for!!! just go around in the new hobbyists section there are a bunch of stickied really helpful threads.
A 180 is not too big to start with! just make sure you will have enough money to put into it. Also you dont just have to go buy everything right away, patience is good and will give your tank more time to cycle/ establish etc.
What do you plan on making it? A fish only? reef? aggressive? etc etc?
What fish are you planning on?
What equipment?
Basically all you do is set it up where the water isnt going to leak all over the place, make sure the tank is level. Then you can fill it up with water, make sure to have some power heads, a heater, and a skimmer, If your going reef i would get a refugium. Add the salt. Then save up money for the rock and sand if you dont have enough. Get the rock first, then hopefully shortly after get the sand. then let the tank cycle, for starters you will need test kits, like ammonia, nitrite, nitrate, ph, calcium and magnesium and alkalinity if you plan on going reef, also a refractometer. Then after a couple weeks to a couple months(however long your cycle takes) you can add your first fish and part of your clean up crew and see how things go. This is when you can do your first water change too. Then you can add more things to it, as long as everything does well. (wait a week or 2)
Any other questions just ask
