stock sheet - update two sheets from one entry

hi thank you in advance for your time x

i have a stock sheet which i would like to update

i have attached the spreadsheet so you can see what i am trying to do... i am not very good at explaining things so i thought the spreadsheet can do the talking for me

two sheets
1. Issued
manually added information regarding clothing and shoes.
I would like to update from this sheet to the Inventory sheet

2, Inventory
automated update from Issued sheet

Item, Size, Quantity

I have linked this In stock spreadsheet to New stock spreadsheet (both in the same sheet)

New stock spreadsheet, manually updated with new stock, which updates the In stock spreadsheet.

if i have confused you :kev:then i apologise but please spare me the time to show me how thank you