youtube mp4 out of musescore file HOW??

Hi fooks,
I joined pro specifically for one big reason: to make a youtube film out of my musescorefiles directly. It enabled my choir members to study their parts with it so that they can actually SEE the score and the blue line and know where they are. I took my file "a thousand beautiful things" and after some trial and error episodes I suddenly found the possibility send it to youtube. I did and got the message back: it is sent and you will receive an emailmessage once the file is published on your youtube channel......This was over a week ago. I never heard back nor found my file on youtube. Since I really need this feature urgently I tried again this morning with another file, but now I cannot even find the possibily to send it to youtube anymore. Not in "Manage audio sources" and not on "share". Please help me by sending the right instructions so that it will work?? The files are below. Feel free to try get the, on youtube and let me know! Thank you so much