Manually insert monthly/yearly Closing stock figues

I dont want to record transactions through Purchase Invoice. So I wont be recording the inventory stock details.
So this creates problem for showing the closing stock amount at the end of any given period.
How do I record closing stock on lets say, monthly or yearly basis manually in manager.

Click the following link to get a general understanding of how to enter closing stock manually by journal entry:

Read this topic Inventory accounting using Opening Stock + Purchases - Closing Stock