Some tutorials we have created for our users:
Add and Optimise a Blog Article To Your Joomla Website
Add an Article And Link The Menu To It
Add an Article With a Menu Link
Editing K2 Items (Joomla v3.6.2 and K2 v2.7.1)
Manage Your Image Galleries (02)
Editing K2 Items - 05 (Clean Text)
Adding an Article With a Menu Link
Embedding An Image Gallery Into An Article