Opening the shop: what you need to hand before you start
The commonest question from those considering selling on a platform is not about commissions but about timing: how long before you can actually sell.
The answer depends almost entirely on what you already have ready. The technical part is quick; what slows things down is gathering documents, if you start looking for them while filling in the form.
The first step is registering the company. You need the registered name, the VAT number, the registered address and the details of the legal representative.
If the VAT number is not yet on the VIES register it is worth dealing with in parallel, because it is the same verification that will later let your foreign customers buy without VAT. It does not block activation, but it is better not to discover it on the first foreign order.
The second step is identity verification for payments, and it is the one people underestimate. It is needed to receive the proceeds of sales, and it is required by anti-money-laundering rules rather than by any choice of ours.
Prepare a valid identity document for the legal representative and the details of the company account on which you want to receive payments.
Without this verification completed you can upload products and configure the shop, but not receive payments. It is where those who put it off, meaning to deal with it later, come to a halt.
The third step is the address the goods leave from, with a contact name and a telephone number. It is needed for order handling and delivery information.
The fourth is the catalogue. Each product requires a description, at least one photograph, the price net of VAT, availability, and for medical devices the CE marking and the manufacturer's name.
On those last two the system is strict: without them, the product is not published. It is worth preparing that information beforehand, because retrieving it item by item while uploading is what lengthens the process most.
Descriptions are written in one language, yours. The translation into the other seven is done by the platform.
You do not need a complete catalogue to begin. Many open with a small selection of items carrying good margins, see how they perform, and expand afterwards. It is a sensible way to start without committing a week's work before seeing a single order.
In summary: gather the legal representative's document, company details, bank account and product compliance information first, complete identity verification straight away because without it you are not paid, and start with a few items rather than uploading everything.