How did you do it? 
Do what?!
The site displays good on full sized laptop browser and in tablet.
What i need to do no is to set it up so that when opened in phone or below a certain size then I get a navbar button rather than the nvbar items stacked on top of eachother.
ok, i think that is a toggle menu.
When you use Bootstrap, you need to add multiple items in your Codepen project for it to work as expected. I see you have added the Bootstrap CSS to your page. Have you also added jQuery and Bootstrap to the JS section? Bootstrap is dependent on jQuery so it’s important to add the jQuery first and then the Bootstrap library.
Thanks. I’ll check.