You've put your head through the sleeve. That won't work out, will it?
You've put your head through the arm-hole. That won't work!
腕通す所、頭通す所とは普段 "sleeve"「スリーヴ、袖」と "neck" 「首、襟」と言われていますが子どもが簡単にわかるように "arm-hole"「＝腕のための穴」、"head-hole" や "neck-hole" も言えます。子どもっぽくて、大人同士には絶対使われていませんが親子の会話なら可笑しくないです。
You've put your head through the arm-hole. (You've put your head through the sleeve.)
腕通す所に頭通してるよ。
That won't work!
それじゃ上手くいかない（よ）！
That won't work out, will it?
それじゃ上手くいかないだろう。（上手くいかないよね？）
You're putting your head where your arm is supposed to go. That's not how you do it.
That's not where your head goes. That's for your arm. You're not going to get your shirt on like that.
ーYou're putting your head where your arm is supposed to go. That's not how you do it.
「腕を通すところに頭を入れてるよ。そうじゃないよ。」
put your head where your aim is supposed to go で「腕を通すところに頭を入れている」
That's not how you do it で「そういう方法でやるんじゃないよ・そうじゃないよ」
ーThat's not where your head goes. That's for your arm. You're not going to get your shirt on like that.
「そこは頭を通すところじゃないよ。そこは腕を入れるんだよ。そんな風にシャツは着れないよ。」
That's not where your head goes. で「そこは頭を入れる場所じゃない」「そこは頭を通すところじゃないよ」
get your shirt on で「シャツを着る」
ご参考まで！
アイルランド 
カナダ 
