If there are no specific instructions, use 2 strands.

Thank you!

I use 3 strands of floss for 14 ct. Aida fabric. It gives a more solid coverage. Two strands are often suggested for 14 ct. fabric but the 'X's are more prominent and more of the fabric will show through. The higher the count of fabric, the fewer strands you would use as the stitches would be smaller. It can depend on the design. If it is a solid stitch picture, you would probably want a fuller coverage. If it is a smaller design with lettering, it might look better where the stitches are more visible. It is all a personal preference. Try a sample piece with different numbers of floss and see which result you like better. It is YOUR project, so do what pleases you. ENJOY!