How to install Ocula from andrewcourtice/ocula

[Johnnywick1]

I,ve got some problems with installing Ocula app.
There is some issues:

yarn run v1.22.19
$ cd client && yarn start --port $PORT
$ webpack-dev-server --env=development --port
/bin/sh: 1: webpack-dev-server: not found
error Command failed with exit code 127.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
error Command failed with exit code 127.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

What commands I need to use to install this app? "npm install" not working

Thank you in advance