A clear brief helps establish whether the service matches your task.
Before you request a document
Start with the purpose: what do you need to understand, configure or record? Describe the intended outcome and any information you already have. An example document can help explain the format you want, but should not be assumed to apply to a different vehicle.
Record the relevant vehicle specification, installed equipment and software version where known. If something is uncertain, say so rather than guessing. Agree the deliverables, prerequisites, format, delivery timing and included revisions before placing an order.