How does ように in this sentence work?
忘れた物を取りに帰るように
As far as I understand, ように goes after 帰る make the sentence means " I take what is lost in order to go back " but It would make more sense if it is " I go back to take what is lost" and why it is 取りに but not 取ってから. I'm so confused.
I think you're getting a few different things confused in this sentence.
Firstly, 取りに帰る is utilising a grammatical structure where "に" is used to indicate purpose. When you want to say you're going to do something in order to do something else, you use this form e.g えいがを見に行く (go to see a movie). Therefore, essentially, 取りに帰る means "return to take".
This site provides a very easy explanation on how to form this grammar and it's meaning: http://www.punipunijapan.com/japanese-particle-ni-purpose/.
Secondly, although ように is often used in the sense of "in order to", in this situation as it's at the end of the sentence I believe it's being used in the sense of making a wish or expressing hope. Here is an example of a similar question that was answered by a native speaker: "ending sentences with ように".
EDIT: ように can also be used in the sense of making a command or request (as explained to me in the comments by user Chocolate). It's probably more likely that this is the case in this situation. Please see their links for information.
Thirdly, 取ってから would mean "after taking" which would give the sentence a different meaning. I.e the speaker wishes they could take the thing they forgot AND AFTER THAT go back, rather than wishing to go back IN ORDER TO take the thing they forgot.
