These are the counterpoint rules.
Melodically everything is allowed except the octave, the tritone and the outlining of triads.
Vertically:
A voice may enter on a soft dissonance.
No octave doubling is allowed.
Direct (and parallel) fifths are prohibited.
Soft dissonances are approached in contrary or oblique motion.
Hard dissonances only by oblique motion. (No parallel dissonances of the same type.)
No resolution required.