2.4ghz and 5ghz are two different types of Internet signals. Think of the signals like two different lanes of a highway. The 2.4ghz signal is like the slower lane, it can carry more cars (data) at one time but they move slower. The 5ghz signal is like the faster lane, it can carry fewer cars but they move faster. So, if you have a lot of devices (like computers and phones) that need to use the Internet at the same time, then the 2.4ghz signal will work best for you. But if you have fewer devices and those devices need more speed, then the 5ghz signal will work best.