Chuwi Lapbook Plus SSD M.2 1T where to find?

Hallo where can I find the ROM256GB SSD? Is that included at factory? Where to buy? Can I use 512GB? Can you send a link where to buy?
Also External memoryM.2 expansion up to 1TB(not included)? Can I take every SSD M.2 ? Or do I need special? Can I take SATA connector? Where to buy this?

I saw in another post that you have found the right one.In fact lapbook Pro only needs to meet the SATA protocol and 2280 length