That is easier said then done with pc knowledge ie the lack of it. If I send you the files will you have a go that is assuming you use Family Historian.
I have read the email the company sent me and as Im not tech savvy do not understand what I have to do.
I wonder if the Family Historian users Zoom group at https://fhuzg.uk would be of interest to you. It was set up by Derek Heritage and intended for real beginners. I have belonged since its inception and have learnt a great deal despite being a decidedly non tech person. A voluntary donation of £5 is requested to cover the cost of the Zoom subscription but it is definitely not a commercial venture. Some experts share their knowledge and experience quite freely. Occasionally the discussions are quite beyond me but that's not generally the case and due either to my lack of knowledge of computer language and terms or to the fact that I have not really started to use FH seriously.
By coincidence last Tuesday's session was on the Merge/Compare feature of FH and seemed quite comprehensible to me. I have two small projects I want to merge, but I must hasten to add that I haven't actually tried to do it yet!