66 cuda electrical

Park brake indicator on means ignition switch is working and power most likely going to everything required for run.
Knowing what trans would save me some typing but anyway...
No start can be starter.
If its automatic trans car.. Failed starter relay, or the most likely failed neutral safety switch.
Its mounted on the automatic trans with a single brown wire attached.
Rather than go under the car at this point, find that brown wire at the starter relay.
Disconnect it, put a temporary jumper wire from that relay terminal directly to ground. This would allow the starter to engage while in any gear so make sure its in neutral.