Melting Point Trends:
The melting point will increase as the branching increases since this would make the molecule more compact and sphere-like (when comparing the branched molecules). So to recap, branching will decrease the melting point when considering linear molecules, however, it will increase the melting point when considering the branched molecules.
Boiling Point Trends:
As branching increases, the boiling point decreases.
As branching decreases, the boiling point increases.