Newbie Questions

Greetings, we are looking to install Flarum on our site and have the following questions:

Can we brand with our site? If so is this a paid feature?
Can we upload files in a post?
I understand you use tags rather than channels. We have various courses that people take on our site, so how do we keep all the math students in one channel and all the English students in another? If it is through tags, how do we make sure only the math students can see the math postings, etc.?
Does a URL show up just as a URL or does it come with a preview? I'm going to include one here so that I can see what it looks like. This is a recumbent bike site on Youtube:
Can we pay for installation on our site? If so, what is the rate?

That's all for now, thank you in advance for any help.

Currently there are no features by Flarum which are paid. Branding and changing the looks of your forum can be done with some basic settings in the admin.
Yes you can upload files to posts, check flagrow/upload.
For users to not see content of others they need to be in permission groups. You can assign students to groups for English etc.
There's an extension that allows links to be embedded, check sijad/mediaembed.