error with runyarn
error upath@1.0.4: The engine "node" is incompatible with this module. Expected version ">=4 <=9". Got "14.18.2"

If the node version you are currently using is greater than 9 and you need to install a node version greater than 4 but less than 9, you can use nvm install 8,nvm use 8
node --version
nvm current
nvm install 8
npm install // yarn
yarn build
yarn start

Hope it can be explained in README.md