Wanna change background colour of my photo -- to white -- for passport use

Got friend with super professional digicamera to take photo of me -- head to shoulders - but problem is the background colour is very dark grey. I want to change it to white.

I'm a total noob to PS (obviously) - can somebody please give me clear, easy to follow instructions, because YouTube's vids are for intermediates and I just cannot follow them -- too fast paced.

Thanks in advance.
iDad is on the right path but imho the first thing you need to do is start with the basics and get familiar with the tools in Photoshop if even the basics or all the videos in the world won't help...

Tutvid has some really comprehensive, easy to follow tutorials on Photoshop. I really do suggest you get familiar with the tools first, then advance to techniques...

This is a good start here...

There are many ways to do it, and the best or easiest way will depend on the image itself. You need to post the picture here, that will make it much easier to advise you properly.