This is a pretty simple exercise that is really good for stretching out your hands and developing your ability to get those really tricky chord voicings. The guitar is very unique in its abilities as a chordal instrument, and the further you can stretch and contort your fret hand, the more interesting chord voicings you can find.
Place your fingers on the highest four strings, one finger per fret. Play this chord. Now switch strings with your middle and ring fingers. Play this chord. Now switch with your index and little fingers. Play the chord. Finally, switch your two inner fingers again and play the chord.
Now move the whole thing down a string set and repeat.
Do this again. Now go back up to the highest string set and put a single fret stretch between your index and middle finger. Repeat the whole process of switching strings and string sets.
Go back and add another single fret space, this time between your ring and little fingers. Next you will add a space between your middle and ring fingers, so there is a space between all of them. Finally, if you think you can do it, add another space between your index and middle fingers. If you want to get really brave, keep going until you’ve got a diminished 7th chord on a single string!
Start out on higher frets, like 12. As your hand stretches you can move it down to make it harder. Right now I can do it at the 7th fret with a 2-fret gap between my index and middle finger, and a single space between the rest, and I don’t have the long slender hands most people think you need to make those stretches. Just keep at it!