Understanding dax

[Balhemkan]

Hi everyone, 

I want to learn how cumulatives work and step by step explanation of measures(dax).Could someone help me with video's or blogs.

Because in YouTube and blog's I can see how we can write formulas but I'm not sure how it will work. I mean how powerbi will understand measures. How we can make powerbi understand easily. 

Can someone suggest me with tips and tricks. 

[MattAllington]

You are asking a very broad question. It's like saying, can you tell me how planes fly without flapping, and how can I fly one. There is a lot to learn. One of the first things you must understand is that Power BI is a database, not a spreadsheet. Storage of data in a database does not have a stored order. It therefore follows that you can't create a cumulative total "down the page" because there is no "order" to "follow".  You need to filter the database so it calculates a total up until a set ID (eg a date). When you lay those IDs out in order, it mimics a running total. 

i have an article here about time intelligence here. It's not quite the same as cumulative totals, but the concept is the same. https://exceleratorbi.com.au/dax-time-intelligence-beginners/