Hello I think the question was about uploading partition.
If it is indeed the case,
in the partitions section there is a button "add a partition" you just have to click on it,
enter the artist's name (if the artist is already present on the site, please use one of the automatic suggestions).
Click on browse, to find the file to add,
inform with the options if it is for chromatic or diatonic, and ideally indicate the difficulty with the stars!