Wow, if that's the most confusing part of Revelation to you, you're doing really well!

The first beast is the primary beast, and the second is like his/her cheerleader, his prime minister, so to speak, or vice president. The two beasts have different attributes. The 1st comes out of the sea; the 2nd out of the Earth. The 1st is a ruler, the 2nd is the prophet pointing people's attention to the ruler. In some circles the 1st beast is called the Antichrist and the 2nd the False Prophet. They play different roles in the deceit of the nations.