You go to the latest release of your version (which is currently 8.2.11) and then you upgrade to the next latest release of the next major release (here: 9.0): https://owncloud.org/changelog/#latest9.0
and then you go to 9.1: https://owncloud.org/changelog/#latest9.1
I wouldn't recommend to go to oC 10 now, there is a minor release soon, wait for that and see if there are still problems. 9.1 is still supported for some time, there is no problem to wait with the upgrade unless you really need the new features.
Don't forget to make a backup before, there is no way to downgrade to a previous version.