To know about how each Display Template associated with each Search Webpart,
In Site Settings Menu --> Select Design Manager-->Edit Display Template and Filter by search Webpart as shown in following image.
Now if you want to upload Customized Display Template, Upload it in Master Page gallery-->Display Template-->Search
Lets take an example of Refiner WebPart. If you edit this WebPart in Search Page ,you will find every managed property( of type string/Int/Date/Bool is associated with Display Template.
If Managed Property is of Type Int or DateTime, you can customize Refiner Webpart to refine it by Slider Template with Bar Graph. (but Note, unless managed property has values , nothing will be shown up)
Once you save changes, awesome slider refiner will appear in Refiner WebPart
take a look at this awesome post