Hi Judit, a long time ago I had a similar dilemma, where there were a large number of courses running on a Moodle installation and we wanted students to see only the courses that they are enrolled into and not see / worry about other courses.
First I removed all the blocks where the courses are visible by default. I also hid the links for the course list pages.
Then I added the plugin https://moodle.org/plugins/block_my_enrolled_courses
Enable this plugin block on the main dashboard page.
Now, users were able to see only the courses that they were enrolled into. (Even the plugin can be customized with CSS / JavaScript to remove user options like hiding courses etc.)
All of this is done through the Plugin + CSS + JavaScript only - without editing any of the core Moodle files.
Hope this helps.
First I removed all the blocks where the courses are visible by default. I also hid the links for the course list pages.
Then I added the plugin https://moodle.org/plugins/block_my_enrolled_courses
Enable this plugin block on the main dashboard page.
Now, users were able to see only the courses that they were enrolled into. (Even the plugin can be customized with CSS / JavaScript to remove user options like hiding courses etc.)
All of this is done through the Plugin + CSS + JavaScript only - without editing any of the core Moodle files.
Hope this helps.