What step do ampoules go on

Ampoule's and serums seem very similar to me so I am not sure which one should go first or if depending on the ingredients each have and people treat them like something more targeted or more “intensive.” I’ve been using one from re:nk on and off and it feels nice, absorbs well, and layers easily, but I also have the Torriden Dive-In Serum and that is where I get confused. They both feel pretty lightweight and hydrating, so I’m not sure if the re:nk ampoule should go before the serum, after it, or if I should just treat them as the same type of step and use whichever texture feels thinner first. Does anyone actually use ampoules differently, or is it mostly just a naming thing?