hey sorry for the late reply :O
you are right, they kind of skip this step in the video.
I added this text to the tutorial now to explain this step:
"
Once you exporter your website and got the files using duplicator you need to upload them to your webhost by using FTP.
Do this by using FileZilla or you can use webftp in your webhost control panel if your webhost provides this.
Upload the two files to your WordPress root folder where you see the folders "wp-content" and "wp-admin" and "wp-includes".
Then in your webbrowser go to: yourwebsite.com/installer.php
Congratulations!
"
heres more info too:
https://laytheme.com/documentation/moving-website.html