how get input from keyboard to Uno?

Is there a way to use the on board usb connection on Arduino Uno for connecting a usb keyboard (powering the Uno with a battery)? How?

If this can only be done with a usb shield: I have a Funduino USB Host Shield. I found that I should use this library for that shield to work.

Then I would like to connect a Logitech DeLuxe 250 keyboard.

So after adding this library, what more must I do to get characters input from this keyboard?

You would need a USB host shield. The regular Arduino USB connection is a client (is that the right word?) rather than a host. A keyboard is also a client. Beyond that I can't help.

if you describe the project you are trying to create someone might have a better idea for how to implement it.

...R

So after adding this library, what more must I do to get characters input from this keyboard?

Look at the library examples for programs that read from USB keyboard.