Slide the chain cutting tool onto the desired link.

Align the push pin of the tool with the pin on the chain, and tighten the tool until the pin protrudes out the other side without falling all the way out.

Stop pushing the pin out when it is just held in by the outer link, so it doesn't fall all the way out. You will still be able to separate the links.

If necessary, repeat the previous step to take off sections of links.

Rout the chain around the front chain rings and rear derailleur.

Pull the ends of the chain together.

Use the chain cutter tool to press the chain pin back through the chain link. If it is difficult to push it back in, the links are not aligned properly. Realign and try again if this is the case.

Reusing pins in chains can cause the chain to fail. This is because the pins are press fit into link. Using a new pin when assembling a chain is recommend for long term use.