Q: How do I filter by multiple tags?
A: Place a check mark next to each one you want to use by using the "Filter" section in the contact screen.
Using the ANY / ALL / NO at the top can limit the list too...
* ANY means that if a contact has ANY of the selected tags they will show in the list.
* ALL means that the contact has to have ALL of the selected tags in order to show in the list
* NO means that the contact can't have any of the selected tags in order to show in the list.
Tags area just gives the full list so you can see the items which use it - but each section has it's own tag filtering.
Q: Is there a way to see a full list of tags (like in an Excel spreadsheet)?
A: Only from that Tags section.