Silver color pimples is easy to install.
Tip: for a heavy fabric use two thicknesses and for a light fabric reinforce with a thermocollant canvas.
To fix :
1. Pass the circle with the tips through the fabric.
2. Place the male part between the tips
3. Place the tools (see sketch) and strike on top with a hammer
4. For the outside of the garment repeat operations 1 and 3 using the female part.