Detailed instructions on how to edit the LCD4/LCD7 DTO P9_21 dependancy to open SPI/UART

I am trying to prototype a handheld sensor with a touchscreen display using the LCD4 and the ADC from Circuitco. After searching the internet for a while I learned that there is a conflict between the two capes at P9_21 and that the LCD4 cape doesn’t actually use it. Furthermore, it looks like the LCD4/7 device trees are loaded at boot and so the only way to fix the problem is to recompile the kernel. I know what lines to remove from the LCD device tree; however, I’ve never compiled a kernel before and there are a lot of different instructions for the beaglebone pointing to various repositories, tools, etc. and I don’t know how to filter out what I need. Has anyone done this before and can you provide a newbie explanation of how to accomplish it?