Carry your gear to the access area and look for a good place to enter the water. Be safe and do not rush because slipping and getting hurt (or dinging your board) upon entering the water is not good material for a story in the pub. Remember to keep the board on the windward side of your body and the sail on the leeward side of your body. This keeps the gear from flipping over you. Also, do not forget to put on your harness. I don't know how many times I have seen people jump on their board only to turn around after realizing they have no harness. It happens!!
Step into the water with your gear lifted up. Slide the board into the water leading with the nose.
When the fin is clear of hitting the bottom (remember that things looks closer than they actually are when looking through water) then drop the tail of the board into the water and grab the mast above the boom with your windward hand. Keep in mind, you have a lot more stability controlling the sail while while holding the mast than holding the boom.
Reach down with the other hand and move the board -- usually by grabbing the back footstrap -- so the whole rig is downwind of you and the nose is pointing in the direction you want to start.
Now grab the boom with the open hand, the clew side hand.
Move the mast hand to the boom as well and float the sail. Your body and the rig are now correctly positioned so you can mount the board. Notice the sail stays sheeted out so there is minimal pressure in the sail.
Keep the sail sheeted out and step with the rear foot onto the board and on the center line between the front and rear footstraps.
While keeping your weight over the foot that is in the water and stabilized on earth, pull the tail of board toward you with the heel that is on the board so your knee forms a right angle and your lower leg is vertical. At the same time, raise the boom above your head by extending your arms. This step and the next are the critical steps.
Now sheet in and get the board moving.
Stand up and sail away. You look fabulous.