to fix it simply clone the repo using git clone and copy the https url on the green code button at the repo page
Fix what you want to fix. Make sure to install node.js version 12.22.12 using nvm install v12.22.12 then yarn typing yarn in the terminal when you clone the repo
Once it is fixed check to see if it is fixed by running localhost yarn start
Then build it by typing yarn build:prod
Once the build is done type yarn deploy