Sorry about the delay in getting back to you. Here is an instructional video that should give you a good idea of what sculpting in Blender involves:
https://www.youtube.com/watch?v=kPkVLgD8--c
Be aware, though, that it's going to take quite a while and a deal of study and practice before you will be comfortable doing any of this. I am trying this myself for the first time and I can produce the greatest looking misshapen lumps, but never anything like what I want. The next step from this would be retopoloizing the high poly beret to a lower poly one for use in-game. Search online for blender retopology. There are a number of decent videos on youtube covering this. then you'll have to bake the high poly details onto the low poly model to use as a normal map. Then comes the fun and games of actually getting it onto a toy soldier's head and into the game. I'm not sure of what that last part entails myself yet.
I'd also advise you look for dedicated blender forums. They're usuallly good at helping new guys if you show you are sincere and willing to work at it.
One other important thing I'd advise is to try to get pictures of actual soldiers wearing berets to use as a model. A beret stuck onto a mannequin head wont ever give the right look.
Sorry I can't help better than this. I'm a total noob too.
