USB host

Hello,
I use a USB Host Shield with a Uno. With USB Host Shield Lib 2.0 I can read the Decription Details from my USB Device. Now I need to send a Bytearray ("FF FF FF FF") via USB. (and later receive the answer) Unfortanaly there is no sample for simple sending and receive data.

Can someone help me?

Can someone help me?

No, because you didn't provide enough information. What kind of device is that? With USB you cannot send just a few bytes, you have to provide a correct descriptor (data structure) to send this to an endpoint. You might take a look at the provided drivers in the USB Host Library 2.0 to get an impression what has to be done.