how to use external crystal?

[Art]

I’ve been following this, but had nothing to add, so doing so silently.
You said you have a scope you should see it with a 10x probe direct to the crystal.

Any varicap across the crystal and you can change the speed of a pic output so a Human can see (maybe not 100us)
There might be a value to cause it to oscillate at startup, but will affect the accuracy greatly if left in place.

If you wet a finger and touch each crystal leg and get it to start you might just need a slightly different value for the parallel caps.

[Art]

I don’t think you actually say you’re using caps, or even a bare crystal. TTL module is even a possibility,
but if it’s a bare two pin crystal and assuming something like 22pF ceramics,
if it’s a protoboard, I recently had an experience where the clock wouldn’t start because the ground
pins of the caps were wound together, and the two disc ceramics face to face close together.