You do not update as in you are replacing any files.
Just download the zip file from main page, extract it and launch the Starmaker Story.exe from the Starmaker 1.8A folder
If you are on about migrating your save(s) the official statement from the developer is to start a new game. Though at your own risk there is a third party migration tool further down the community posts.
I will note if you have not played in some time there is a lots of new content and the images have been reworked in the early game. So it is highly recommended to start a fresh save.
