TL;DRA saved mapping from a file's columns to customer, timestamp, meter, and quantity — built once on a sample, then reused.
A template says which column identifies the customer, which one is the timestamp, which columns or formulas produce each meter's value, which rows to skip, and which columns make a row unique.
It is built against a sample file and processed explicitly — uploading a sample stages nothing until the operator hits Process. Production uploads then reuse the template: upload, review, approve.
Where it happens in Sonic
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See it on your contracts
A walkthrough on the agreements and files you actually bill from — not a slide deck.