If you are just starting out with Xerte then you need to explore how it works and browse and search around for some guides and videos etc.
There are lots of videos that are old but still mostly relevant and lots of educational organisations have created guides and examples that are some times public facing.
A few links to get started:
The Xerte wiki
xerte.org.uk/wiki/doku.php?id=start covers all the features and options. e.g. export is under project properties
xerte.org.uk/wiki/doku.php?id=project_properties
and as I replied previously you will then need to extract your export and upload everything it contains to a web server. Many people use Xerte together with a virtual learning environment or LMS like Moodle in which case you can also export as SCORM and then upload the SCORM export to the LMS/VLE.
There are lots of conference recordings available via
xerte.org.uk/index.php/en/news/blog/158-videos which might give you a better understanding of how Xerte is used and why.
And as I say there are lots of videos online created by users of all levels so a relevant search might help.