I am the father of a one-year-old, so I appreciate the unique challenge presented here. First, you'll want to set up a detailed study schedule. Give yourself at least 2-3 months to prepare. Consistency is more important than the total amount of time invested - it's much better to put in 1 -2 hours a day than it is to do the occasional marathon 5-6 hours sessions, which, I imagine, aren't really an option for you anyway. During the week, study time will probably only be possible after the kids have gone down in the evening. (My daughter goes down at 7, so if it were me, I'd shoot for something like 7:30 - 9.) On weekends, this may require looking into baby-sitting, or developing some ninja-like skills timing your study blocks to match nap-times.
Next, consider getting some good apps. These are perfect for sneaking in a 15-20 minute session. Our entire course is available for free via our app:
https://www.veritasprep.com/gmat-iphone-apps/
Work through the Official Guide:
https://www.amazon.com/Official-Review-O ... guide+gmat
Use an error log to track what kinds of mistakes you tend to make:
https://www.beatthegmat.com/mba/gmat-error-log
You'll want to schedule consistent practice exams. Eventually, you'll take one per week. Take the free ones from mba.com. Buy the two additional tests there:
https://www.mba.com/us/store/store-catal ... ack-1.aspx
When you dissect your practice exams, make a list of strategic adjustments you can make before the next test. Do drills to address categorical weaknesses.
Keep us posted!