I am really new to blender and I am scrambling to learn as fast as possible however I am currently stuck. I have modeled a basic barrel and textured it as best as I can, I would like to add a dynamic kind of grunge to the barrel and I was assuming I could do this with nodes. The only tutorial I can find though is from back in 2015. Any ideas where I should start to achieve a grungy look? This is where I am currently. enter image description here