Defining BCWS of a cost resource i.e payment plan

Hi,

I'm would like to budget my project which has approx. 20% labour costs and 80% material costs. Budgeting the labour costs is quite clear via the work contour option in the task usage view. 

How can this be achieved for cost resources? Can I eventually define the payment plan of a supplier ( for example 5 payment steps ) for one activity only? 

What is the best practice to achieve budgeting ( BCWS ) for cost resources?

I'm working with the following version of Project:

Microsoft® Project® Online Desktop Client MSO (Version 2308 Build 16.0.16731.20182) 64-bit

Thanks in advance  

Best regards