magnetic snaps for fastening leather, canvas, heavy weight cotton, polyester, denim, tarps, etc.
Mark position of snap pieces by pressing prongs into fabric hard enough to leave an indentation.
With very sharp small scissors, cut the indentation just wide enough for the prongs to go through. Put prongs through to wrong side, place the disk over the prongs then bend prongs inward or outward. (I usually push my prongs to the outside)
TIP: Make sure to put the magnetic clasp on the right side of the lining, before attaching lining to the outside of bag if this is where they are going.