below is link for very descriptive video on data blending by tableau consultants
https://www.youtube.com/watch?v=6cMri9oXLfw
Also Check my example on data Blending as below
data looks like below
2 different data sourses are defined using 2 sheets in workbook above .
click below link for dashboard full example
https://public.tableau.com/profile/amol5536#!/vizhome/Data-BlendingSample/Dashboard1
https://www.youtube.com/watch?v=6cMri9oXLfw
Also Check my example on data Blending as below
data looks like below
2 different data sourses are defined using 2 sheets in workbook above .
click below link for dashboard full example
https://public.tableau.com/profile/amol5536#!/vizhome/Data-BlendingSample/Dashboard1