Oh snap you're Stranded!  What you do next can decide your fate and path moving forward.   For those of you familiar with skyblock, a lot of this will look familiar, but being in a vast ocean adds some difficulty, but also makes a couple things easier.  Obviously you don't have to worry about falling off the island and dying, but you do have to worry about dangerious weather and the difficulty of operating in water.  Remember, the JEI is your friend, and if all else fails use this book to help you learn the ropes.