just space them evenly away from body i usually have my the same as if i was bench pressing just upside down, have them out horizontally till biceps and triceps are horizontal.
Don't worry if you do put your hands out to far, because it'll work your chest more for bench press and to far in will work your triceps more.
When you get better at them, then proceed to putting legs on something high and putting your hands on the floor and making yourself push more
body weight. Then after that you can add weight in a vest or backpack which is even harder.
But Yes dont worry i remember back in the day when i couldn't do many but after practice they are now easier
but if your really worrying about your posture while doing a push up, best thing is to politely ask someone to check if your doing them correctly and your posture.