Hi
firstly the reason I asked exactly what version you are using is because there were some changes in different 3.11x updates relevant to this. We announced and released Xerte 3.10.5 back in March with important instructions to upgrade as soon as possible
www.xerte.org.uk/index.php/en/news/blog/...ailable-upgrade-asap
and obviously the instruction now would be to upgrade to the latest revision of 3.11x which is 3.11.11.
So your first step is to upgrade to the latest version which I think includes the changes needed to allow you to use and see the xml files you have uploaded.
Regarding the video and multiple choice question you don't say what page type you are using but again there are significant changes in 3.11x that may be relevant so I suggest you get upgraded and then start that as a new topic.
HTH
Ron