You can write what you need in the margins or create columns in your existing logbook, or start a new one. I like the Jeppesen logbook. It will last a long time. The big Sporty's log is good, too. Presently, I use the Jepp logbook. It has a few extra spaces, and a few more can be made, for things that you may want to track, like time in type, or a particular kind of flying (aerobatic, tailwheel, utility, etc) for insurance or other reasons.
Whatever you choose, get a small document safe that will protect the log(s) under most forseeable circumstances (fire, etc). If you go with a computerized log, back it up, and it's a good idea to keep printed copies.