Hello @sohughes1,
To add the slider for the gallery page jut go to edit mode of the gallery and then there you will see Gallery Setting at right corner . In Gallery Setting you see Link To Option . Here select the option Media File and save the setting .
For proper info refer to below screen Shot :
https://image.prntscr.com/image/T4O2iGB9Ri27W8YBbZt0iw.png
As for the category you can simply click in eye like structure when hovering over the category image .
Hope this helps .
Please write back to us if you have any confusion further .
Best Regards!!