BOOTCAMP NEED HELP PLEASE READ

When I get to the part where it says where do u want to install windows.I click on Drive 0 Partition 4: Bootcamp

and it says beside the yellow triangle: Windows can't be installed on drive 0 partition 4 (show details).

I click format then I click ok. But then it says

We couldn't install Windows in the location you chose.Please check your media drive.Here's more info about what happened: 0x80300001.

I have no idea what I have to do but as it says my media drive I think it has something to with my USB which is

SanDisk Ultra USB 3.0 Media

I have followed all the steps but this still occurs I don't know why this occurs even though I have done all the steps correctly (or so I think)

The other time I tried to run Bootcamp it would say: Windows installation cannot be continued because a required driver could not be installed.

Other times it says something about NTFS and that the drive doesn't have it.

Please, I really need help because I have watched more than a dozen videos and read more than a dozen articles and I still can't fix my problem.

My computer is iMac (21.5-Inch, Late 2013) Processor are 2.7 GHz Intel Core i5, with 8 GB 1600 MHz DDR3

Graphics are Intel Iris Pro 1536 MB, the startup disk is Macintosh HD and 1TB of Storage with 852 GB left and I am allocating 500GB to windows.

I have had to partition my disk back more than 4 times and by now it is getting frustrating and I could do with some help please-Thanks.