How to create "Bar chart" sales data?

[Pree]

Hello All, 

I want to create Bar chart. In the Bar chart, i want to show values for 4 months. e.g. For first month June, it should fetch data directly from file. For next month July, it should add the data from June and July and show it for July Bar. For August, it should add the data from July and August and show it on the August bar. 

I do not how to do this in Power BI? Do we need to write a Measure for it? How to write the measure for this Query? 

Please guide me. 

Thank you. 

[lbendlin]

Please use the Quick Measures feature for this, it has examples of running total measures.