If you didn't create and preserve the physical inventory adjustment worksheets for 2018 then hopefully you have a backup of your data from the time of your 2018 count.

Restoring this backup, creating physical inventory adjustment worksheets for 2018, and applying these to your current database is beyond the scope of this forum.

If you don't have a backup then you will have to manually enter adjustments working from your 2018 year end Item Valuation report.

It would be a good idea to contact your Adagio Consultant for assistance with this issue.