citation order

Hi everyone, I am trying to insert citation on my paper. When I inserted the first ref  it was alright. It did show [1] at the end of the sentence where i wanted to show but when I inserted the second ref, [1] changed into [2] and [1] went to my second sentence.

I tried to google if anyone has the same problem but I can not find one. Could anyone help please.

Thank you.  

I suspect you are using a numbered style that alphabetizes the citations rather than in order of appearance.  Or you have put a citation into a text box (ie fig legend).  what style are you using…