Good evening
Sorry but looks like iframe html tag is sanitized from the text block and it will be not displayed here 
without modification of the theme looks like this is not possible but i just opened case in our tracking system:
Hello!
Could we add a Youtube video now? The problem is fixed? Is very urgent for me
Good evening
Sorry, but it’s not yet fixed
I can do this manually for you, please provide admin access details here privately and I will make these changes for you
Good morning,
I added that for visible menù:
.main-navigation {
opacity: 1;
visibility: visible;
}
How to show also the menù in case you scroll down the page?