Everything depends on the photo you upload, because that is the only place the AI can read your pattern from. Shoot the fabric flat, in even indirect daylight, square-on rather than at an angle, and close enough that one full repeat of the print is clearly visible along with the weave. A phone camera is fine. A shot at a steep angle, in yellow indoor light, or too far away to resolve the texture gives the model less to preserve — and what it cannot see, it will approximate.
Avoid shadows falling across the cloth and avoid photographing it crumpled. Both bake information into the image that the AI has to interpret as part of the fabric rather than as lighting, and creases in the source often survive into the output as if they were part of the material.
Then check the output like a buyer. Is the motif the same size relative to the cloth? Are the colours yours, or a nearby shade? Is the weave still visible, or has it smoothed into a flat print? The instruction explicitly tells the model to reproduce your fabric rather than design a similar one, and it holds well on clear source photos — but reviewing the print before a picture goes on a listing is the check worth making a habit, exactly as you would proof a retoucher.
Use the notes box for anything specific to your cloth: show the selvedge edge, keep clear space at the top for a caption, include a ruler for scale, keep the border visible. It is read like a brief.