If you are looking at a view and want to add a filter, use the Filter button. 

With Filter you can filter forms by: Status, Owner, Started, Modified, Status date, Reference fields, List fields, Yes/No fields, and Date fields. 

Depending on your filter choice, further filtering options will be available. For example, if you choose a Date field, such as Incident Date and Time you will be presented with additional filter options to narrow in on the forms you want to view. 

After you make your filter selections click OK and the filter will be applied. 

At this point you can either + Save as new view or Remove filter. 

If you + Save as new view you'll be able to name the view for future reference, share it so other users can view it, add other filters to further refine forms, and select columns for the view. 

If you Remove filter you are directed back to the "All" view, or the view you came from to start the filtering process again.