How to compile and install Linux Kernel from source code

Basic question.. How do you call functions from a (non-kernel) driver's source file?

I have a USB (VID0A46 / PID9621) Ethernet Adapter and found driver source code for it,
qop_kernel/drivers/net/usb/dm9620

I'm interested in using the device and adding/modifying that driver.

But not sure how to get started (compile, load, call functions). For example, I installed gcc and plugged it in , but how do I call load it, in order to call its functions.. like "dm_write_eeprom_word"?

Uid: 712136417
Europe server
Actually, i wish for Shenhe not Ayaka... and lost 50/50

One way to make the kernel compilation faster is to add a -j(number) flag with number being the number of cores your cpu have example make -j4 if you have 4 cores.Can actually make a pretty significant boost. Without it from the time command that I got it took me 2hours ish vs 25min~ with the flag enabled (4 cores)

Thank you

thank you

thanks