I don't understand the translation order of スカートは試着して買わないと心配だ。


I think how to translate this could be...  
① スカートは  
② 試着して  
③ 買わないと  
④ 心配だ  
That should make the translation go...  
"The skirt, I tried it on, If I don't buy, I feel worried."

But in the book it says...  
"If I don't try the skirt on before I buy, I'll get worried."

Could anyone explain which word I should translate in the correct order? What
grammar is this sentence using?

