You should always UV map before doing any type of texture work, wether it be displacement, bump, or standard texture work. It makes it easier on you.   Pins are used in the UVspace, not the regular object space. They are used to help lock down a particular part of the UVMap so that when you relax the rest of the map, the area "pinned down" is unaffected.  This can be used in several ways. Most common uses is to get part of an area ...say the ears, of a head relaxed and laid out then use pins to lock that down while relax the rest of the head. Another way is to pin down the outer corners of the UVMap and then relax the interior so that the map relaxes relative to the pin. Sometimes it works and sometimes it doesn't. My experience with Headus UVLayout has helped me to understand the tools before I got Hex2 and I have to say, In someways Hex 2 is neater but in other's, UVLayout is better. I guess I'll be using both.