Ok so, to begin with, you can paste all this code in the custom code HEAD section at page level (diplay the page panel, click on the page options, go down and it’s the first box of custom code)
Those are the style declarations so they need to be in the HEAD section.
<style type="text/css">
html{
margin: 0;
height: 100%;
overflow: hidden;
}
iframe{
position: absolute;
left:0;
right:0;
bottom:0;
top:0;
border:0;
}
</style>
Add the following code into the box below, the box for code that will appear before the /body
<script type="text/javascript" src="https://s3-eu-west-1.amazonaws.com/share.typeform.com/embed.js"></script>
Now add the iframe into the designer view in a HTML embed:
<iframe id="typeform-full" width="100%" height="100%" frameborder="0" src="https://boussenot.typeform.com/to/t00RTE"></iframe>