Sprite Sheet Issues

I am new to Unity and Game Dev in general. I am having extreme issues with Unity and the Sprite Editor. The Sprite Editor doesn’t splice my Sprite Sheet and I have ensured that it is on “Sprite Mode” and “Multiple” and nothing happens. I have read countless of Forums and watched videos and nothing seems to work. Also, one of my Sprite Sheets file cannot be read and I have formatted to be PNG, PSD, etc and to no avail. Can someone please help me?!

For reading PSD you need to import PSB-Reader (or so) in Unity Package Manager.
With the first problem: Maybe they are sliced, but i think you can only see them when you click the objects.