First off avoid buying any tools.. ya don't need em.
Secondly what you do need is a 1) a pair of pliers 2) a hammer 3) a few thumb tacks
Third take the tack place it on the pin on the wristwatch band and place something underneath it.. take your hammer and tap and tap until the pin becomes dislodged.
Fourth take your pliers and pull the pin out..
Fifth repeat the 3rd step on the additional links..
Sixth take the pin you pulled out and place it into the new connections ya want and VOILA' how to change the length on your metal wristwatch band.. it's easy I promise!!