Can someone provide me step by step process including config as how data extraction and upload functionality can use BW as tool with integration with EM: I want to have an article with screenshot just as we have for TM with BW.
I don't think we have detailed a step by step configuration document for SAP EM to SAP BW here. You can check Kevin's wiki post where he nicely drafted lot of information for us.
You can check these:
Basic Settings - SAP Library - Basic Settings for Event Management
SAP EM BW Initial Load - Initial Upload (SAP Library - Basic Settings for Event Management)
SAP EM BW Delta Load - SAP Library - Basic Settings for Event Management
Click refresh button on those links, it will show you dropdown and you can check BI Settings for each visibility processes.