Create stock forecat

Hi, I'm attempting to create a measure/column that will show stock available at the end of each week based on the sales, forecast and an opening stock.

Attaching link to an example of my data. Number of weeks may vary

Thank you

https://drive.google.com/file/d/1335g1M2KNZAn3nVEWEP1LXXzeURLk9lU/view?usp=sharing