HELLO ISSUE WITH THE %OF TOTAL SALES IT SHOWS ALL ASS 100%
Find attached all the DAXs i wrote them correctly according to the video , can you please tell me what is wrong 
Can you please check that you have the correct relationship between fact_InternetSales and dim_SalesTerritory?
Hello , as you see it is as active many to one 
Ok, any other filters applied on the page or slicers?
no slicers are activated
there is something strange about the measure it says SUM of % Total Sales Amount, it is not supposed to apply any additional aggregations. You cannot sum percentages
Yes it shouldn`t sounds like this it shouldn`t be the sum of % , i don`t know do you have any solution or i should just pass it.
I don't think you are using the correct measure here, by default Power BI cannot apply additional aggregations on measures. Looks like you are possibly using a column here not a measure.
Your formula of %ofTotalSalesAmount should be equal to :
%ofTotalSalesAmount = Divide(Amesures[TotalSalesAmount], Calculate(SUM(fact_InternetSales[SalesAmount], All (dim_SalesTerritory[SalesTerritoryCountry]), All (dim_SalesTerritory[CountryOrder])))*100
Instead of
%ofTotalSalesAmount = Divide(Amesures[TotalSalesAmount], Calculate(SUM(fact_InternetSales[SalesAmount], All (dim_SalesTerritory[SalesTerritoryCountry]), All (dim_SalesTerritory[CountryOrder]))*100)
It will solve your problem I guess!