Purple material texture.. is driving me nuts

If i am asking here its because i’ve tried my share of question and answers. I soends a good 80 hours this month trying to solve this issues. Most would have quite by now. But its impossible i cannot find the answers. Just know one can give me a straylight answer. Like. How about just telling me were to go from scratch to get material texture that wont turn pink as soon as i load it… Just so i can get the start up cube to shine a difrent color that i can play with texture node to get some roughness out of it. Like 100% of the video and basic lesson… When i fresh install blender and set the world hdrs the world just stays black. And then once i put materiel regardles of what they are. It turns pink. You can send me a easy melateriel texture in a blender file iver a square box it will stay pink. I might be actually 100 of hours into learning blender. And aven gone past doing an animated gradiant overlay.