If you are going to stick stickers you need the following things:

• dust-free cloth
• cleaning agent
• degreaser
• painting tape
• measuring tape
• spatula or bank card
• pin

The sticker must consist of one part.
For this method, the substrate does not have to be completely flat.

• Stick the sticker on the left and right with painting tape.
• Determine the exact position using the measuring tape.
• Is the sticker in the right place? Stick a strip of masking tape in the center of the sticker
  from top to bottom.
• Now loosen one of the sides and fold it to the other side.
• Remove the back sheet (backing) to just slightly before the painting tape.
• Cut or cut away the back sheet.
• Rub the sticker firmly from the center with a spatula or bank card.
• Then loosen the painting tape on the other side.
• Remove the masking tape in the middle.
• Flip the other way and remove the remainder of the back sheet.
• Now attach the other side in the same way as above.
• You can remove any air bubbles by pricking them in the middle with a pin and rubbing
   them from the outside to the hole.