Help

ok guys i am now messing around with directx function hooking, but the examples i found are just confusing. most of the tutorial are people showing their implementation of the hooking. no explanation!

Now i want to try this on gta sa, so i've found the pointer to IDirect3DDevice9 on the internet.
so i just need to know what is the steps considering we dont have to find the device

ok guys, so i understand how to jmp from an address to my own function and how to jmp back etc.

/*Noob alert*/
I've try midfunction hooking on a simple program where when you hit the buttom it decreases the health. I have used the cheat engine disassembler and manage to find where the location of the code that decreases the value, which looks something like this (sub health,1) . Now that is where i hooked(yeah i know a sub instruction is 2bytes and i need to get atleast 5bytes to do the jmp so i included the next instruction which was 6bytes that give a total of 8bytes so i fill the remaining 3bytes with nop and replace the 6bytes instruction that i did not want to overwrite in my code cave(myfunc) so yeah lets move on considering i know all these stuff)

Now this is my question, where do i hook from if i want to draw a simple text on the screen.
Guys i'm not asking how to use directx functions to draw text or rect etc, i will figure that out later.
i just want to know whrere to hook from.
I know i might sound like i don't have a clue what i'm talking about, but guys please bare with me
thank you