After planting water in well with a seaweed based product such as Seasol to give them a boost and stimulate new root growth.
Water regularly for the first year until well established and then occasional watering will be sufficient. Flower colour can be intensified by reduced watering.
A good layer of mulch around the frangipani tree will conserve moisture and protect the roots. Fertilize 3 – 4 times per year with 3 to 4 month fertilizer.
In cooler climate your frangipani will need special attention. Plant against a north facing wall to maximise the effects of winter sunshine, mulch well with a dark coloured mulch to absorb the heat and cut back on water and fertilizer in the winter months to discourage new growth that could suffer from frost damage.