Welcome to CR and the wonderful world of SW! Knowing fresh water means you understand the nitrogen cycle, now throw the rest out the window lol. No seriously, and this is just my 2 cents... But maybe start out very slow, grab some "clean" live rock and do a FOWLR or fish only with live rock. Get your feet wet and absorb as much knowledge as you can and then slowly get into corals, or just dive right in and hope for the best. Salt water can get very expensive, very quickly and tough lessons become costly.
You could spend hours, if not days researching one topic, such as lighting, or filtration, or additives, etc., etc. Best to take it slow and ask lots of questions! Use these forums during your build and ask opinions prior to any purchase you make and you will get some solid advice. These forums are some of the best pages of information found on the internet and the folks here are very helpful.
Best of luck, looking forward to seeing your tank come to life.
