Another = an other (as in an apple): refers to singular Other = more than one, non specific amount. He suspects she's talking with other men. He suspects she's talking with another man.

I will write down 2 examples so you can understand better. I want another computer I want the other computer "Another" is used to refer to something or someone that has already been mentioned. In your case, you talk first about One man, and after another one. Other is used to mentioned something for the first time or different to something that has already been mentioned.