If you use MODX without composer.json, you need to download this file from official MODX repository into the root of your project and run composer update.

Just run

composer require sterc/csp --with-all-dependencies

Then you need to add installed package into MODX with shipped console script

composer exec sterc-csp install

This will run database migrations and register everything needed.

Almost the same commands but in reversed order:

composer exec sterc-csp remove
composer remove sterc/csp

Custom tables will be deleted along with all other package entities.