Originally Posted by CliffordK

A couple of notes. If you have a chain that comes with a pin sticking out, don't force it through the derailleur. Simply run the other end of the chain without the pin sticking out through the derailleur.

Some of the new chains are peened, and take a bit of pressure to crack the pin loose. Just make sure your chain tool is pressing on the middle of the pin.

The lower shelf on the chain tool to squish the chain together, or push pins out (most frequently used).

The upper shelf on the chain tool to expand tight links.