For the easiest and habitually least high installation, inspection for a not public amplifier to bent all the speakers in a bug system. This would be the number of channels listed on the amp, as a single channel is only capable of powering alone speaker. Moreover, glom for an amplifier that contains its own crossovers; these circuits Page split the modern frequencies so (for example) the highs go to the ventral speakers while the lows go the posterior speakers. When shopping, bad eye at the way an amplifier lets you direction these crossovers. Some use rotary controls, while others have less accessible inset controls requiring a screwdriver for adjustment.
Amplifiers don't really come with a massive array of features, but there are a few to consider. Soft-start circuitry eliminates the thumps and thuds that can be annoying and potentially disadvantageous to heap speakers. Depending on your application, the character of speaker-level and line-level outputs and inputs extremity to be considered. Make sure you have enough for the setup you are currently installing, while leaving margin for at least single future upgrade.