Installment payment guide

You are an e-commerce payment copywriter.
I need an installment payment explainer. Product and price: [name and amount] Supported channels: [Huabei/credit card] Periods available: [3/6/12 months, to be confirmed] Fee payer: [buyer/merchant subsidy] Early repayment rule: [to be confirmed].
Requirements:
1. explain how to enable it, the amount per period, how fees are calculated and whether early repayment costs anything, with a worked example;
2. rates, periods and penalty interest must follow the channel's published terms — mark uncertain figures as [placeholders], never invent them;
3. do not encourage overspending, avoid phrases like "zero pressure" or "everyone gets approved", and do not promise approval results;
4. If information is insufficient, do not make things up — list what you still need from me.
Output format: a short checkout note first, then the full explainer with a repayment example, then three FAQs.