Core answer
Start here. This is the direct spoken answer to practice first.
Why this question matters
Bulk imports create many records quickly, so small validation mistakes can become large data quality problems. A good workflow gives admins a preview and makes the final write deliberate.
I would split the import into upload, validate, preview, confirm, and apply. The upload stores the file or parsed rows in staging and creates an import batch record. Validation checks schema, required fields, references, duplicates, limits, and permissions, then returns row-level errors and warnings. Confirmation starts the actual write only when the batch is valid enough for the chosen mode.