How a hobbyst can use fiber laser?

Gentlemen,

I´m a hobbyst and I´ve heard about fiber lases.
There are modules on sale on eBay, some are big and rated at 40W optical power.
Most of them have a fiber connector.

But how do I use the fiber??
Can I take the connector and put it close to the part I want to cut/mark? do I need lenses?

I saw many videos on youtube and searched for sites, none of them show how a hobbyst can use it.

Is there a site with more information?

thank you!

The end of the fiber is outputting 40watts of invisible light photons going in a straight line.. you still need a focusing head to take that light and concentrate it enough to be useful. Also be aware that 40watts is enough to blind you instantly so be sure you keep the machine contained to prevent that. And buy glasses rated for the wavelength that have the correct protection.