Where can I find video tutorials on how to Edit Device Responsive screen mockups?

Hi, I hope you are doing well. I just purchased the Multi Device Responsive Screen Mockups. I need to find tutorials on how to edit the Photoshop files. I can’t find them any where. Can anyone in this forum give me a clue to where I can get help? I thoughth there would be documetation with the download but there was really no instructions for how to edit these mockup files. Again can you help?

Thank you,

Try Youtube

Try on Youtube