How to make a Helper/Service that would be included with composer and autoloaded?

I'm in the process of making a Library (a single php class atm) that handles some document-related stuff. I'm also adding a Helper that allows for quick access to some of the Library features (mainly to use inside views). I know how to add and use Libraries, Helpers and Services.

But if I post my Library + Helper + Service config on the github and then request it in another new project with composer (which will put it in "vendor/myname/mylibrary/"), how do I make so the "helper" function in the new project will also look into my library /Helpers/ folder and that my library Service config would be merged with both CodeIgniter and the new app configs so the "service('library')" would work out of the box?