D.A.T. has a good method for marking the location and holes. Many emblem have studs which are offset from one another so it makes marking the holes for drilling difficult. Using D.A.T.'s method would eliminate several possible mistakes.
The link I provided the OP has a center punch that is made with a high and low tension adjustment. This is very useful especially when center punching a panel on a vehicle. To much tension could cause panel damage ( dent ) that spreads past the emblem drilled hole ( holes ).
To help eliminate possible damage to the panel center punching, I would support the panel from behind to minimize panel movement. If the panel can't be accessed from the rear, I would use a magnet with a heavy pull, or a glass suction cup on the front to the panel so I could ( pull / hold ) the panel from movement during center punching. I would start off using the low tension adjustment on the center punch. I would also center punch "thru" a piece of masking tape. It will help reduce spider cracks in the paint when center punching.
Once the metal has an acceptable divot from the center punch he can move on to drilling the hole. As already stated, it would be best to use a small bit first and work your way up to the hole size desired. Remember to hold the panel firmly either from the back side or the front when drilling. There is the possibility of damaging the panel if it's not supported when drilling. It would be best to use brand new drill bits. New bits will require less force when drilling.
Laying out, marking, drilling and mounting an emblem is relatively easy if a few precautions are observed. For future reference, it's always best to pre-drill any holes before paint. Paint fractures are a real thing when having to drill thru a painted surface.