Creating Burndown chart using scheduled completion dates and actual completed jobs

[billybob123456]

Hello, (Look at reference image above)

I am creating a dashboard to record current and completed jobs. The data is getting pulled in automatically with 2 date columns for current jobs and completed jobs. The 2 dates include: actual completion date and scheduled completion date. So the current jobs come with 2 date columns and the completed jobs come with 2 date columns. I am trying to create a bunrdown chart that displays the amount of scheduled completed jobs and the actual completed jobs per month (see example picture above). So in july, you have two columns, Red column(SCD: Scheduled completed jobs) and blue column(ACD: Actual completed jobs). If 15 jobs are scheduled to be completed in july(red) and 10 jobs are actually completed in july(blue), then those should display in the chart.

Below, you can see a very rudementry chart with a small data set. Dark blue being SCD and light blue being ACD. I did this in a method that does not work in all instances so I am trying to figure out a knew method. 

I am very new to power BI but I ended up using Inventory Item ID (unique values) as a way to count the amount of jobs in that month. Below you can see what columns I used and where I used them in the visualizations tab:

If you look back to the first image, you can see the line starting at x=START, y=100. Lets just say that we are starting with 100 jobs at the start of the year and we want to know by december, how many we schedule to get done. We want to continueously subtract from the intial amount of jobs, so by every month, you know how much you have left. To do that, I was thinking I could subract the count of completed jobs from the month before, and then once we get to the months that havent happened yet, you subract the shceduled completed jobs from the month before. You can see in september( lets just say that its september next month), we dont have any actually completed jobs because thats in the future. So there are no completed jobs, so you would use the scheduled ones to know when you'll eventually get to 0 jobs left. Again I am new to BI so I may be thinking this way wrong but any help to this would be great! 

Thanks for taking the time!!!