Help please!! Oxygen theme is killing me

I have two problems that I can’t solve.
1. The slider. I got it to work once and then I accidentally erased the page thinking it was a different page. I went through all of the steps again but now it wont work. It either pops up with a 404 message or it posts as just a post, no sliding ability, it just looks like a blog page.

and 2. I made a custom header I want to use. When I go to appearance there is no header option. If I go to theme settings I have the option of putting in a logo which shows in the right place but it scales it down so that its small and unreadable. I made sure that I checked keep original size and when I change to a manual smaller size it crops the sides off.

Please help me!!