Iben,
Meta courses can be used for several different reasons. Your situation would make a meta course a good idea if you don't want to create two entirely different courses and run them. It may be a little tricky with the different schedules, but it might be a time saver for you. How you set it up and use it varies a little bit between different Moodles... but here is a senario that might help:
You have a meta course with all your resources in it. Your child courses are the ones that you or your school has set up as different sections of this same course. You hook them up to the Meta course. You can use Groups http://docs.moodle.org/23/en/Groups to separate out the two different courses. Be sure to turn the groups on in the course edit settings page. You will then have a section 1 and section 2 group options in your gradebook in a drop down window. If you set your activities up with Separate groups, the two groups won't see each other in the forums, etc. You do all your grading in the meta course. Your students will all go to the meta course to see their grades and work with the content. There are even ways to set up a assignments etc. that would be for one group only. I would only do that for a few or I would get really confused!
When we worked with 1.9 we had separate meta courses that remained stable and we pointed the new sections at them every semester, because in that version, you couldn't have any students in the course to make it a meta. With 2.x we are now having section one with the content and then pointing the other sections at that with the meta link.
I hope that helps. The tricky part will be for you to keep track of the due dates in the different courses.
Paula Clough