Shopify's documentation for Indonesia comes down to five rules, and each one creates a job for your expert.
Payments through a third party. Without Shopify Payments, checkout needs a third-party provider plugged in. That provider determines the payment methods customers see, what each transaction costs and when funds arrive. Your expert should connect it, place live test orders, process a refund and confirm a payout reaches your account before launch day.
Prices in rupiah. The store currency is the Indonesian rupiah (IDR). Fix it before products are imported, because changing it later means rechecking every price.
Manual Tax, no automation. Indonesia gets Manual Tax only, with neither Shopify Tax nor Basic Tax on offer. Every rate, every taxable product and the treatment of shipping is entered and maintained by hand, and third-party tax apps are permitted. A careful expert documents each setting and asks you to confirm it with a local accountant rather than guessing.
POS hardware from retailers. Shopify's hardware store won't send devices to Indonesia. Card readers and receipt printers come from a third-party retailer instead, and each model should be checked against Shopify's supported hardware before you buy.
Indonesian end to end. Shopify supports Indonesian in the admin and at checkout, so the writing left to your expert or copywriter is product pages, policies and any custom theme text.