I’m happy to be able to provide my first tip
Thanks to mr_xing who helped me to solve my problem.
So, if you want to creat a table with a filter like this one here: https://www.w3schools.com/bootstrap/tryit.asp?filename=trybs_filters_table&stacked=h
You need to copy the whole code into a HTML widget AND also into the page>settings>Add code>Footer.
But you need to delete the “div” part from the Footer to avoid having 2 tables.
PS: I realized that this code is causing problems with my navigation bar.
I hope we’ll have the chance to see a bric dedicated to it.
It would be great