That is not a video but After Effects project file so to change pictures in frames you have to:
1. open AE project file that you bought on VH
2. find precomposition with placeholder of picture that you wish to change
3. change that picture
4. do that for all of the pictures that you wish to change
5. Rener your composition to format that you wish
If you don't know what I'm talking about that mean that you don't know to much about After Effects so I recommend to learn some AE basics f. eg. from that link: After Effects tutorials | Learn how to use After Effects CC
And if you wish to get instruction step by step what exactly to do and where to click and how - we have to know that exactly projest file so you have to send it to me - before that I can't tell you what exactly to do because each composition/ each project file can be done different.