Just uploaded K2 to my site which already contains many articles. Imported all items to K2 and then edited one. The results show on the back end but not on the front end. Can't activate it.Have checked out forums and docs but can't see how to do this.Any help appreciated.Thanks

you should have categories and subcateories in k2 now depending on the structure of your sections and categories in joomla before the import.
create a new menu item say k2 category, and select the category you want to display, items should appear

Thanks William. I did that and the entire category was installed but not in the format I wanted. At the same time, I tried to access the item I had created via the K2 panel (now they are not available via the Joomla control panel) and, each time I tried to access the category, I was returned to the control panel. Seems I don't have access to my items now.

Next step. I considered uninstalling K2 but there seems to be no instructions as to how to do this.

Can you provide a guideline either way or point me in the direction of which documents I should read?