Change Data in sheet Excel

I puted one graph on my form with object Microsoft Excel Chart and I Would like to change data in my graph but I don't know how.

Many peoples said to me you can use chart1.Worksheets("sheet1").cells(2, 3).value = x but I received all the time this error "Method or data member not found". I putted Chart1 before worksheet because it's was the name for my object and in this object,the graph was build with sheet1.

I would like to change data on sheet1 in the object Chart1.

I try to with Dim x As Excel.Application ...But is not better.

I need some help.
Sorry for my english.

Thanks
Redg