Simply configure your macaroon HEX string (e.g. from Polar) and the REST API address in a .env file. See .env.example.
$ git clone https://github.com/getAlby/regtest-website.git
$ cd regtest-website
$ yarn install
$ cp .env.example .env
# edit .env or set a `LND_URL` and `LND_MACAROON_HEX` environment variable
$ node fourohtwo.js
$ open http://localhost:3030