Drop down header needs coding

I have a project which I’m working on, however I would like to add a feature to my site which is also featured on this website: www. ilenoliukgo.co

At the top of the page, there is a button “say Hi” when pressed a section is dropped down with content in it.

I need the same thing coded for me, however with one slight change and than is the “say hi” button is not connected to the top of the page, I need it a lot lower down as a separate button.

I don’t need any content added to the drop down box, just the function coded.


Thanks
Chris