Heya mate,
There is no book that can teach you, no video nor a pfd or whatever. It is you who needs to do it. You need to step over that line that holds you from touching.
A tip to cross the gap would be: start mildly. Like touching a shoulder when you bend in to talk. Or an elbow. When sitting down, touch a knee. Not always, because otherwise it is noticable. You will be stigmatized as a touchy pervert

. You will notice that , when there is a certain amount of interest, she will start touching you as well, if she hasnt started already.
From there on, steadily grab more of your balls and amp up the kino. But start at the start.
Dont forget, it is you who needs to cross that line. Nobody else can do it for you. Nothing else will show you how to. It is you.
cheers