Is it better to get Botox on multiple desired areas from the start?

Since it's my first time getting Botox, should I try one area first?
I am wondering if it would be better to do the place I've been concerned about together.

I wonder if there are many people who get treated at just one place first and check the progress.
I am wondering if there are cases where facial expressions or impressions feel awkward when multiple areas are treated simultaneously.

For those of you who are getting Botox for the first time, how did you get started?