What's the best way to set a time target for a course?

I have an upcoming trail race and I'm unfamiliar with the course. I do, however, have a Garmin course provided by the race director which I've uploaded to my watch.
I'd also like to set a goal time to make sure I'm on my pace target.
Is there a good way to do this?
I tried setting a distance and time goal under the training menu, but it said the course navigation had to be canc