When target price is met start a trail stop order - what's the best way to set this up?

[Grayfox87]

Good day fellow traders,

I am looking to set up a conditional order or script that would do the following.

When target price is met, then set up a trailstop order for the equity.

For Instance:

Stock is at $100 currently

When price hits $120 then set up trailstop for -10.

Thanks, I'm sure the question has been asked 10000 times, so a link to any answer would be appreciated.