The word 'serial' is a computer term which refers to the idea of one 'bit' at a time, or rather 'one process after another'. Like melody in music, one note occurs at a time, such as with a saxophone, flute, or similar. Piano and drum set are both 'serial' and 'parallel' by nature, in that many melodies [thought of as harmony] and/or rhythms can occur simultaneously.
In this study of serial coordination, there are 57 exercises presented in this e-drumbook exploring 'melody' on the drums. For every rhythm presented is a diagram indicating 'R' for the right hand and 'L' for the left hand (keep in mind that 'R' and/or 'L' could be any limb or sound source to be motioned/sounded).
A good way to start out with these exercises is to playback each audio sample, developing a fluidity and familiarity with each rhythm, while examining the corresponding diagram.
The drum in the right speaker indicates the sound designated "R" [or right hand] and the drum in the left speaker indicates the sound designated "L" [or left hand].
Once familiar with these rhythms, try applying said rhythms at different tempos, dynamics, and sound sources [i.e. multiple drums, prepared piano, etc]. Enjoy !