Take it slow and be yourself, help out when you can, or when you’re asked, and the number one thing is to be good to their mom.
It’s very obvious when we do this and kids read that stuff immediately.
Here’s what you do: treat the kid like another adult and engage in conversation and bonding the way you would if you were stuck in a house with random guy or girl.
Most teens are cynical and standoffish to new boyfriends so you have to expect hostility initially.
Don’t go turning on the young man’s Madden game and professing your “skills” in hopes that the video game will bond you to him.
Guys this is hard if you aren’t a lover of children; I cannot stress this any harder; if kids annoy you, or if they get in the way for you, then stick to women who lack kids.