There are many ways to propagate and plant-out native Hawaiian species. One of the most thorough and helpful books is Heidi Bornhorst's book, "Growing Native Hawaiian Plants". The easiest, and best way to obtain natives for the novice gardener is to get them from a reputable nursery. That way all you have to do is know how to transplant (if necessary) or plant-out when you are ready.
In order to help you successfully plant, we've created the following guidelines:
Plant most native Hawaiian plants in a sunny location in soil that is well-drained.
Make the planting hole twice as wide as the root ball or present pot, and just as deep.
Mix course red or black cinder and course perlite or compost if the soil is clay-like and drains slowly.
Place some slow-release fertilizer at the bottom of the hole.
Carefully remove the plant from the container and place it in the hole.
Adjust the soil level so the plant is at the right depth (the top of the soil should be at the same level as the top of the hole).