Before you begin take this 1 rule serious ..
NEVER RUSH ANYTHING IN SALT WATER . ALWAYS TAKE BABY STEPS
My very first recommendation would be do as much research you can to give yourself a better understanding of saltwater and what it involves . I would also suggest a keeping journal of everything you did to your tank , you can list dates along with your test readings. I always like listing salinity when you do water changes , also how much of a water change , this journal will prove to be one of your most important tools in your possession .
once you start your journal you will be able to see if things need to be addressed
example you see your nitrates or phosphates rising you can do a water change to bring them down before you encounter the nasty counter part algae ,
same with ammonia keeping a close eye on it is important also , another good thing is if you ever encounter a issue you can fall back on your journal to see when things started going wrong. it can actually help you diagnose the problem . I call it the saltwater bible the best thing I ever started. this will make your journey in saltwater so much easier.
I would first familiarize yourself with the cycling process as many fail to do this correctly . This is the very first important step if not done correctly your looking
to fail. we want you to succeed the first time . very important don't rush through this process ,
be sure to test your water 24 hrs after you add your ammonia source , test your water periodically through your cycle , the average cycle takes anywhere from
4 to 8 weeks all tanks are different this is just a basic time frame .
this link will explain the cycling process.
Cycle your salt tank - Aquarium Advice
Once you get through this hurdle we can start the next part
you don't want to get overwhelmed to fast as that's when bad things can happen
you never want to overload you train of thought to fast