How to add Particles.js to my background and then make it static

Hey there, I’m trying to achieve something like with the particles.js in the background staying static while text scrolls over it.
The two things I’d need help with is
a) How to add particles.js to the background (And generally any container)
b) How to keep the background static while text scrolls over it.
Thanks for any responses, Tim
EDIT: also, some basic pointers on how to create the dropdown menu in would be great.

I would think that the particles.js would be in a fixed postion container with a z-index less that the main body… something like this:

#particles-js {
position: fixed;
z-index: -1;
background-color: #3e2224;
top: 0;
right: 0;
left: 0;
bottom: 0;