Move a NC site from one hosting to another

Nextcloud version (eg, 12.0.2): 13.0.x
Operating system and version (eg, Ubuntu 17.04):
Apache or nginx version (eg, Apache 2.4.25):
PHP version (eg, 7.1): 5.6


What would be the process to move an existing Nextcloud instance from one hosting to a brand new other (just installed), knowing that (so far) I just get admin access to the target new instance, the source instance being managed by a third party admin whom I can probably ask for data and files.

So, what’s intended here is just move the whole existing Nextcloud instance (data, files) from one place, say, to a completely different one, say

Thank for the advices.

Looks like the answer might be here