Sunset is not an add-on. It is the name commonly used for the final version of Money Plus Deluxe that was issued by Microsoft. If you downloaded and installed it from the link in the second"sticky" thread in this forum:
https://social.microsoft.com/Forums/en-US/479281b2-90f9-42ca-85f7-644fc6e1e5c3/download-microsoft-money-installation-files-solve-activation-and-some-other-errors?forum=money
then you already have it. Note that since you are running Windows 10, you should update the mnyob99.dll file as described in the first "sticky" thread in this forum:
https://social.microsoft.com/Forums/en-US/d28d6921-1f01-430f-b33e-f5a3ec47077b/important-patch-for-money-plus-maybe-20062007-mnyob99dll?forum=money
If you can open your previous Money.mny file with Sunset then you are all set. If not, or if you need help with any of the above, post back with the details of what you did and any error messages.
Bill Becker
