Need help building marlin for ender 3 pro

I’ve been trying to put Marlin together for my printer with no luck. I have an ender 3 pro with an SKR mini E3 v 1.2, a TFT35 E3 v3.0 touch screen, and a BLtouch. I’m using visual studio code with platformIO and autobuild marlin. I’ve gotten to the point where it will build but it wont upload, I also don’t want to mess anything up by uploading something wrong and destroying the printer. Any help would be greatly appreciated.