Which costs should I set up first?

Start with product costs, then logistics, then payment fees, then overhead. That follows the life of an order: you buy the product, ship it, get paid and keep the shop running. Your P&L is your profit and loss statement. Each cost you add makes one more margin on it true.

Product costs alone already give you CM1. CM1 is what you keep from your sales after paying for the products themselves. It tells you whether your products earn money at all.

You do not need all four to get value. Anything still missing is flagged, never counted as zero. So a half-finished setup gives honest partial answers, not a confident wrong one. How long the whole setup takes depends mostly on how many products you sell.

Each kind of cost has its own page in the sidebar. Product costs go on the Products page. Shipping, packing and returns go on the Logistics page. Payment fees go on the Transaction fees page, and running costs on the Overhead page.