Just for reference:
https://forum.inaturalist.org/t/how-do-i-add-new-observations-with-different-dates-but-the-same-location/33601
https://forum.inaturalist.org/t/single-specimen-single-observation/32330
https://forum.inaturalist.org/t/making-multiple-observations-of-the-same-organism-s-when-it-has-undergone-a-notable-change/31271
I usually put the URL of the other observations in the comment section of the observations