Hi Channabasappa
We have mapped this same scenario in previous project
For Each Sales Order of Solar Plant create a project,
For each activity like civil work , Electrical work required for installation of Solar Unit maintain as Internal Activity
and if you have agreement to bill stage wise you can maintain Milestone in Project
maintain Solar Unit as FG and assign it to External Activity. After PR,PO and GR it becomes Project stock.
you can create Sales order with account assignment WBS and Create Delivery.
Please check and Revert Back