They are located between the automation and tag buttons at the top right of the board. Filters do not impact what other users see - they only affect your view.
In the filters panel, you will see some quick filter categories:
To access advanced filters, navigate to the board view of your project. Click on the filter icon at the top right (it looks like a funnel). This will open the filters panel and allows you to set filters based on custom fields.
Click the "+" icon to add filter criteria. You can select the custom field, operator (Equals, Not Equals, Contains, etc.) and the value to filter for.
Use the AND/OR buttons to string multiple filter criteria together in one filter.
Once you apply filters using the Quick Filters or Advanced Filter, it will instantly filter the records shown on your project view. You can add multiple filters to narrow down the results further.
The currently active filters will be shown at the top, so you know what filters are applied.
Any filters you set will remain active even if you navigate to another view and come back to the board view later. So you do not have to reapply filters each time.