Scope 3, the emissions in your value chain rather than your own operations, is the disclosure most entities are least prepared for, and the one AASB S2 gives the most room on. You are exempt in your first reporting year. From the second year it is mandatory, measured under the GHG Protocol's 15 categories, from purchased goods and services through transport, waste, business travel and the use of sold products.
The relief is a trap if you read it as a delay. A credible second-year number needs a first-year baseline, and a baseline needs a data pipeline: supplier invoices, purchase records, freight documents, travel bookings. Entities that spend the relief year doing nothing end up publishing a number in year two that they cannot explain and did not see coming.
The accepted path is to start spend-based (emission factors applied to what you bought, by category) and upgrade the material categories to activity data over time. Spend-based numbers are imprecise but complete, they identify which categories matter, and they are defensible as a first estimate provided the method is disclosed. Materiality then tells you where supplier-specific data is worth chasing.
The mechanical burden is document volume: thousands of invoices and statements, each needing to be read, coded to an emissions category and factored. That is the part CarbonAgent automates: pipelines into your ERP and inboxes read the documents, keep NGER and GHG Protocol reconciled, and leave every figure linked to its source, so the Scope 3 line in your report survives an auditor's trace.
Scope 3 sits in the metrics & targets pillar of the disclosure requirements. If you have not yet scored yourself against the rest of the standard, start with a gap analysis.