To preview your redactions, you can click 
Play within the player controls to see if all your effects are set as desired.
After you’ve made your adjustments and you’re ready to create a copy of the redacted version of your file, click 
Process from the Shortcuts Bar or from the Task List Panel to process the file. Please note that you do not need to click Process after every single edit you do. Instead, click it after you have made all of your adjustments and redactions.
Processing time will vary depending on the size of your video and the number of objects in it. You have an option to Schedule Processing after hours.
After processing is complete, watch your entire video to verify the video is correctly redacted.