I do not have my final logo yet, can I start?

Short answer: Yes. Build your shop with the logo you already have, even a low-quality one, and replace the file later.

You can absolutely start with a web-quality logo (72 dpi): it will look good enough on screen to compose the visuals and put the shop together.

The print-quality file only becomes essential when orders are processed, to physically produce the marking.

When the right file reaches you, upload it into the existing logo rather than creating a new one: every product will follow automatically. See I have received my real logo, how do I replace it.

If you have no logo at all, the demo shop has generated two temporary ones for you — one for light products, one for deep products.