Just starting out can't find anything

Ok, i’ve just registered today and I can’t figure out how use the software, or even where to find it. Most ai image generation sites just say “enter text here” pick a model and click button. I know years ago you could Download stable diffusion, is that still the case or what? if yes how do i find it? and before you tell me imagine you are explaining it to a toddler, I really don’t get all the technical stuff.