How to sync with Onedrive on Android?

you set it up but have you synched

look at my earlier screenshot I wrote it in red that you only add the graph folder in logseq after you sync

Is there a way to find where my graphs are stored?

you don’t find it. you tell logseq where you put it, which you placed it there by yourself first by telling foldersync where to sync the onedrive folder to