As the man of steel says reasearch is the key
I reasearched books & forums, visited my LFS for almost a year before moving from Fresh - Marine
You can have a tank as easy or difficult as you want, a basic reef (Soft Corals & Beginner Fish -Clowns, gobies etc) IMO isnt far to difficult to keep healthy as long as you are willing to put in the time & money & know yours & your Tanks Limits
Regular topup, changes, tests etc. are a must, but a understanding of how a Saltwater tank & Fish work should be 1st on your list
As mentioned above, have a read of the stickies & other posts on here & if (& you will) have any other questions, ask away