How to finetune materials?

Hey guys,

I’m relatively new to Unreal and just tried setting up a test scene with a character I’ve created a while ago. I imported the static mesh, set up the shader and applied it to the mesh. However, the textures don’t quite look as they’re supposed to. The color is way too dark and they’re too glossy. I remember a colleague finetuning those channels with some values in Unreal but I can’t recall how exactly he did that. Anybody here who can help me out on that?

Thanks in advance!