Easiest installation would be to use one of the mounting bolts or studs for the external coil to mount the condenser to the bike. If you have a bonding wire for the ground at the coil put that with the condenser mount on the same fastener.
You can trim the condenser's pigtail to fit. Splice it together with the wire that comes from your points where it goes into the external coil.
If your external coil has the DIN numbers marked on the terminals make sure you attach the pigtail/points wire to the #1 terminal. The #15 goes to the ground. Switching those two terminals backwards will result in a feeble spark.