Step 1: Write note against note (1st species) counterpoint in the upper stave.
Step 2: Write note against note (1st species) counterpoint in the lower stave.
In both cases, the intervals should be major or minor 3rds or 6ths, perfect 5ths and perfect octaves. Parallel perfect intervals should be avoided. Use only the notes of G major scale (with F#).
In the first version, start with the perfect 5th or octave. In the second, use a perfect octave. In both cases, finish with perfect octave.
Here is the PDF file for printing.
When you are done, post your time and feedback to comments.