From the Contacts Homescreen:
1. Click on the button, looks like a funnel, to the left of the Columns tab (top right of Contacts screen) See: https://madshot.net/032661ed8edd.png
2. Choose 'Create Custom Filter'
3. Top line for 'Choose Option' is the field that you want to create a filter on. (Color Tag, State etc.) See: https://madshot.net/a14af041dc2a.png
4. Middle line for 'Choose Option' will be the filter 'rule' you choose from the dropdown options. Eg: Is, Is Not, Contains, Does Not Contain etc. (Options will vary depending upon the field type.)
5. If you're creating a filter for a custom field with text, type in the exact word of what you want filtered.
a. You can add multiple options. Eg: To filter a state you can have it set to look for the abbreviation and full word. See: https://madshot.net/c556a0dc8f24.png
6. Save As: will be the title of your Filter. See: https://madshot.net/d196050000ce.png
7. Created filters will only be visible tot he User who created it. If you want available to all Users, check the box requesting this. See: https://madshot.net/c280b52ee239.png
(only the creator of the Custom Filter will have the option to edit or delete it)
8. Click 'Create Filter' to finalize and Save. Once created; custom filters appear in a dropdown format to the right of your existing built-in filters. See: https://madshot.net/93a22a303256.png