How do we handle a transfer from one old desktop (Windows 10) to a new desktop (Windows 11)?

I am in the process of transferring my files from an aged desktop which is running Windows 10 Home edition to a brand-new desktop running Windows 11 Home. I was told by a Reckon employee that it was just a simple exercise to transfer the data to the new computer – problem solved. So, I have transferred the data and whilst the new computer accepts new data, the program crashes when I seek to save entries. Any help would be appreciated. I understand that the software cannot be held on both computers. Would appreciate help.