“As you're well aware, all requests for tech support are to go through me.”
You're the manager of a tech support department at a company. People are supposed to e-mail you when they need help with their computers and other technology. Then you choose an employee from your staff to help them. One coworker doesn't follow the rules, and always calls one of your staff members directly instead. She just did this again, so you write an angry e-mail telling her not to do this. You begin the e-mail this way.
As you're well aware, all requests for tech support are to go through me.
This expression introduces something that your reader or listener already knows, but you want to remind them of.
"As you're aware," is a formal phrase. A more casual version is "As you know,":
As you know, you're supposed to go through me for any help you need with tech issues.
You can add "well" to talk about something that your audience knows well already:
As you're well aware, we don't allow smoking in the building.
You can use this phrase when you're annoyed by someone who keeps making the same mistakes, or just to be helpful.
To "request" something means to ask for something. To talk about the things that you ask for and count them, use the phrase "a request for ___":
My request for a transfer has been approved!
"Tech support" is short for "technical support". Most large companies have some employees whose job is to fix other employees' computers, install software, etc. You call this job, and the tasks that these people do, "tech support".
Putting these together, "requests for tech support" means the things that you ask for technical help with.
This is a formal and strict-sounding phrase that means that something must happen or is supposed to happen:
All students are to return home immediately after school unless they are participating in an approved after-school activity.
This means that the students have to go home.
"You are to ___" is strict-sounding and usually used by people in authority.