its a bit of a mess since the wiki page isnt done by a native english speaker.
But you folow the link on the wiki for the firmware or download it directly from Marlins page. I wound up using info from the FYSETC master set up with the new Marlin build (2.0.5).
Follow the guide on installing VScode with PlatformIO for Marlin, its on the site.
once loaded up, in VScode you need to on the left side you will see a list of all the various files and folders. click on Platformio.ini and go to line 21 and make it say:
default_envs = STM32F103RC_fysetc
there are also some premade config.h and config_adv.h in marlins github.
from there you will find a FYSETC folder with different models of boards. you will need to replace the config files in the main Marlin XXXX folder with these. from there you set up the print area of your machine, give it a name if you want, set your esteps and thermistor types and most importantly, set the stepper driver types. I found i needed to set them to the TMC2208_standalone to not get errors. you can do more advanced settings but thats just the basics.
if you need faster help Im also in the marlin discord and 3DPrinters discord, im not sure if im allowed to post links to them but they are easy to find in a google search.