May I follow up on this question?

I am trying to offer a contest to my local programming team using the CodeForces/Polygon platform. Initially, I would like the contest and problems to be private (accessible only to my team), but after the contest is held, I'm glad to make the problems accessible to the public.

Is this possible with Polygon/CodeForces, and if so, how? I was able to create a contest using Polygon, but I can't figure out how to make the contest available to my team.

Do I need to use the "Mashup" contest feature?

I am confused by this paragraph:

"Mashup is a special type of training contest, which consists of public problems from past Codeforces rounds. Also it is possible to add Polygon problems to mashup contest. Such contests can not be made public, they are only for personal training purpose. Also it is allowed to add mashups to groups. To specify additional information about mashup contest, use Gym contest edit form."

What does "it is allowed to add mashup to groups"? I thought a mashup is a contest, and a group is a group of users — how can you add one to the other? Where is the "Gym contest edit form"? Is there a way to create contests that aren't mashup contests? I can't find the necessary button/form for that.

Thank you for your help!

• Godmar