Newbie question…
I’m a Linux user with various cloud-based storage systems. One of which is Yandex Disk, which offers cheap storage.
Q. Re. Yandex. If I create a Cryptomator vault locally how do I upload any changes to the Yandex site, do I have to install the Yandex client app?
Thanks!
Welcome to the Cryptomator Community 
Yes.
Cryptomator Desktop only encrypts your files and stores them in a location accessible by your filesystem. If you want those encrytped files to be uploaded to the cloud, the location must be the synchronized cloud folder.