I want to add custom code to a navbar that is made on Webflow. I have my navbar set up but now want to edit an interactive feature. I already have the code for that feature as well. What I am trying to do is have the navbar start on the bottom of the opening page, and then as the user scrolls down, the navbar goes up and sticks to the top. An example of it can be found on this website: https://www.thedistrict.co.uk/
So how do I apply the code to a navbar I already made on Webflow?