Know how what? You can’t put your children first if you’re working. It’s just basic common sense.
Maybe not in the workplace, which is why it would make sense for employers to think twice before expecting people (not just parents) to be available round the clock. If everyone were expected to be available to be called into in work at 1.00 am (outside of a scheduled nightshift) nobody would be able to make any plans or arrangements, or to have any sort of life outside of work.
You can certainly go to work in a job with reliable hours (which most probably could be with a bit of imagination and give and take) and put your children first. Most parents do exactly that, and work so that their children can have best the start in life that they can give them.
The fact that SAHMs also do other things doesn't really stand up in this context, though, Callistemon, as many working mothers do those things too. It takes more organisation, but it is perfectly possible to work, have outside interests and see that your children get to enjoy theirs too. When children are at school, their clubs and classes happen in the evenings, for one thing, and for another, many volunteer organisations are staffed by people who work during the day, so they, too, have meetings out of working hours.