There are only two more minor chords left to learn and, in actuality, you could get away with just playing the F and B fingering to get to any chord by moving up the neck of the guitar. However, it is still worth your time to learn these two remaining chords, as their open note sound is a staple in so many songs.
The A Minor is actually the same as the B minor moved down a whole step. The only difference is that you do not need to bar your first finger across the top since those notes are the default already on the guitar without needing to press your fingers down. Therefore, the finger position is adjusted differently from the B Minor in order to free your pinky finger to augment that chord. I mention this only to encourage you to use the fingering shown here for the open A Minor chord instead of that of the B minor finger position. Trust me, later on you’ll apreciate having that pinky free.
Practice the A Minor like you have the previous chords, eventually incorporating transitions between the A Minor and the other chords you have learned.