Draw Propane (H3CC(H2)CH3), then remove both of the hydrogens on Carbon 2, and add two Methyl groups, CH3, to the Carbon.
Can't draw the 'Bromo-' part as we don't know which Carbon the Bromine atom is on.
EDIT: A structural formula shows how the various atoms are bonded. There are various ways of drawing this and you will need to be familiar with all of them. A displayed formula is a type of structural formula and shows all the bonds in the molecule as individual lines, where each line represents a pair of shared electrons.