Waterfall visual - Budget to Forecast

Hi, haven't found in search so hoping someone can assist.

Looking to transition to PowerBI from Excel reporting, self taught but a beginner!). One very common way of showing movements we use is waterfall charts. We show movement from one old data set view to latest view, for example, Budget to Forecast. I want to show:

• Starting position and end position
• Material movements by assset ordered in size of variance
• Under a certain threshold (ie. a small movement over time) group in an 'Other' Column

Am struggleing to do any of the above (add a start position, then order in time, and group others), so any assistance greatly appreciated.

Below for example a simple data example and excel chart - Two Tables, one called Budget with all the budget data, and one called Forecast with same layout and relationships, with the Forecast data. I have added some extra numbers in yellow as helpers to explain the data link between tables and final chart. 

Any help greatly appreciated! Let me know if I can add any more details.