The example you posted above nelly.com is a professionals store so I would image they have their photos taken for the purpose.
Link to a TF file like what you mean specifically and someone might be able to be more specific. Alternatively you could ask the author
32 validation issues – mostly easy fix
Footer needs work
there is a lot of white space in magna, auto, Incididunt – the padding, spacing and structure needs attention here
contact, about etc all dead links?
In theory then (make sure you have the right file downloaded from here (when you click download, then select ‘installable WordPress files only’) or you will end up with the ‘missing stylesheet’ error), go to appearance >> themes >> upload and follow the steps.
Do you have WP installed on your domain?
Completely agree with Tom and Iman that this may cause potential confusion.
Aside from the possibility for people to think it is a requirement [definitely the main potential issue], looking at the process for those novice buyers I wonder what % will know all of their admin, FTP etc details that are requested?
Could this add to the confusion?
If it is different then potentially but would need to go in one at a time and also be noticeably different in features or design. Good luck
Try installing it via FTP – that error message is usually a hosting glitch and can be overcome using this method.
You need to login with the account which purchased the file and then download and check the documentation for the theme that will cover this.
Anything beyond this you can ask the author of the file, but again it will need to be using the buyer account so they can verify your purchase