Roy,
An additional thing to be aware of is that if you change the chain, most chains today are "peened", which means that the ends of the pins are intentionally flattened so that they don't pass through the plates easily. When you use a chain tool to remove links, the peened parts of the pins are ripped off. This means that you cannot reuse those links and you cannot use a chain tool to join the two ends of the chain. You must use the master link that is supplied with the chain to attach the two ends of the chain. If you use a chain tool instead of a master link to rejoin the chain, that link will be severely weakened which can cause the chain to snap when under load, throwing the rider over the handlebars (ask me how I know!).
This differs from the old-fashioned, no-master-link chain that you probably have on the bike now, which can be separated and rejoined using a chain tool (but preferably not the same link each time. .