Marlin Upgraded on a ender 3

Hello, i have a ender 3 pro and been wanting to upgrade the firmware to marlin. but im having great difficulty.1.Installed VScoder2.Downloaded marlin and the config files3.moved config files to marlin folder.( as website instructed)started VScoder and did everything needed to build marlin in platformIO and hit the build button. has its going thru its thing it says 1failed (ATmega1284P). i robooted everything, even the computer and still the same failer.Now i may have made things worst cause i been looking to find how to fix this problem for two days. i did a few things some suggested online and now i can the marlin back up in platformIO. Can anyone help me or guide me to the right person? ill even do teamviewer.Help!!! lol

Correction, Can't get marlin to show backup in PlatformIO