should cypress be installed in the client or not code example

Example 1: open cypress window

./node_modules/.bin/cypress open   // just cypress open wont work

Example 2: cypress run all files in folder

I think you're looking for --spec path/to/folder/*.js

You can run all the tests in a folder, or even in all subfolders of a folder

example:  --spec cypresss/integration/subsetA/**/*.js
would run all .js files in all folders under the "subsetA" folder in cypress/integration.