What to do after ExitBootServices in UEFI?

Question

C++ / C#

Let's say I wrote the simplest heloworld application from this article: Programming for EFI:
Creating a "Hello, World" Program . Having not googled anything worthwhile except for this article (the rest were either about nothing or repeated it), I went to look for how to clear the screen and how to write a simple video driver (I understand that VGA, that is, 0xb8000 is no longer supported in UEFI. Who can , tell me if this is so), but I did not find anything. But I found information about ExitBootServices, which, as I understand it, removes UEFI services from memory and transfers control to the operating system. I still haven't figured out how to use it. Well, I'll call him, and then what? Need to load your drivers? In that case, which ones? AHCI and video driver? Trapping interrupts? (by the way, are they still in UEFI, like in BIOS?)