A Melon grab is where the front hand grabs the heel edge between the feet. The board is kept flat. This grab is often a lot easier than trying to grab the toe edge. It will also help create a more balanced posture in the air due to its compact nature and acts as a key component towards dialling Method grabs.
Start directly behind the kicker at a point that will enable you to safely land on the table top or just over the knuckle. Re-create a funnel shape with your turns with a focus towards riding straight up the centre of the kicker.
Aim to be flat base as you travel up the kicker with your upper body aligned with the board. You have the option of maintaining that flat base or transferring the pressure slightly to your toes as you initiate a pop or ollie.
An ollie will often float more easily into the grab than a pop. You can ride up the kicker slightly lower than normal to reduce the travel distance for the grab.