I'm upgrading to high Sierra by clean install. I have my bootable USB drive. I've already erased my disk. I clicked install. I chose my SSD Drive. I clicked 'agree'. It finished 8 minutes of loading. Went to a black screen then white with grey apple logo. It's stuck on the first 1/10 of the loading bar. It doesn't seem to be loading. Then after a couple of minutes it's back with disk utility/macOS Utilities and its like I have to start over again. I don't get to the WELCOME part. I don't understand what's wrong. What can I do about it? Please help me.