In this type of counterpoint, no dissonant intervals are allowed (no 2nds, tritones, 7ths, augmented and diminished intervals and their compounds).
When you use the consonant 3rds and 6ths, parallel motion sounds well. but often we aim for contrary motion between the voices in order to have the balance and independence between the parts. Parallel unisons, fifths, and octaves of course are forbidden here.
The numbers above and below the notes indicate the intervals with the melody. 10 and 13 are compound intervals larger than an octave: 10 (octave + a 3rd), 13 (octave + 6th).
Here is the PDF file for printing. After you complete this exercise, post your time to comments.
By the way, if you do these types of exercises for a while, you will start to notice not only how your music theory skills improve but also your musical thinking and analytical abilities are sharper as well.