It’s very simple to use, take the Eb disk for example. We move by three notes. There are three groups of four notes which we move around. The same colour block indicates the transposed note. If you are are transposing from piano (concert) to Eb sax you move in an anti-clockwise direction. If you are are transposing from Eb sax to piano you move in a clockwise direction. For example, what is a B concert on the Eb sax? Jumping anti-clockwise from B to next dark coloured block -> gives you an Ab.
Simularly F# -> Eb, Db -> Bb and so on.
To transpose from Eb Sax to Piano just move clockwise from block to note of same colour e.g. C note on an Eb sax, is Eb note on the piano.
Looking at the Bb disk, we move by two notes. There are only two groups of six notes which we move around. So you just jump a block to transpose the note.
For example if you want to know what note to play on a Bb sax to sound an F#, jump one block in a clockwise direction -> Ab.
Simularly Bb -> C, Eb -> F and so on.
To transpose from Bb Sax to Piano just move anti-clockwise from block to note of same colour e.g. G note on Bb sax is F on piano.