I've recently bought a capo and have troubles with decoding clues on the box.
First two columns are clear: if you want to play in C or in G, do not use the capo (that is, place it above the nut); then moving the capo by one fret will increase change the key by one semitone. The only subtle misunderstanding is that I thought that classical EBGDAE tuning corresponds to E minor / G major and cannot see where does C come from: it is neither parallel nor relative key.
What intrigues me most is the last two columns. The grid seems to depict first five frets of a six-string guitar. But what is the meaning of four small bold rectangles and the purpose of the Fret/Nut table as a whole? Is it a handbook for those not knowing how to count to five, or there is some hidden sense I cannot understand?