What is the difference between a cohort and a group?
See #1.2 in Groups FAQ
Can I synch cohorts with LDAP groups?
This is not currently available as standard. However, the tracker issue for this - MDL-25011- offers a patch which works on versions up to and including 2.3. It has not yet been tested on 2.4.
Where can I practise with some ready made cohorts?
I want to enrol a cohort of students into a category
This is not currently possible. Please see MDL-36951 for the reasoning behind this.