Updating the button text is possible via the customizer, as mentioned earlier please browse to “Appearance >> Customize >> Featured Slider Options >> Slider Elements On/Off”. There you should see “Read More Text”, which you can edit as per your need.
Updating the links of the button or slide is handled from the slide where it was added. Please go to “Pages” in the admin panel, select the slider item and update the link of the page. This will be automatically reflected in the front end.