You can use the lasso or polygonal lasso tool, this tool is usaly located at the top left of phototshop
Next. You must drag or click around the area you wanna copy, for example if you use the footmans head then you must select his head with one of the lasso tools, then after you have selected the head press Cntrl C
Now you have copied the footmans head texture, go to the jaina texture then press Cntrl V, and walla you will now notice the footmans head on the page
Next. Use the move tool, usaly the very first tool. Then select the footmans head and drag it onto jainas head, after that, go to Edit and then Puppet warp or Free transform
Then. Just rezize the pic with those tools until it fits in
Tips: Puppet war is for advanced users
Sometimes copy pasting textures will look crappy
Always look at the model wrap before copy pasting
GOOD LUCK!!!
