Screw threaded mounting rods into number.  Apply spacers if desired.

 

Tape group of templates together and tape the full set to the wall. Use the template to mark locations of holes, and drill holes.  Use 5/16” bit for good results.

 

Glue number into holes using epoxy or similar type glue.  Double check that everything is level.  Using masking tape or similar, tape number to wall until glue is dry.