Cry it out method

Can anyone tell me what constitutes the cry it out method? I have a three and a half month old and don’t plan to use this anytime soon ... she’s too young for that and I’ve heard not to start that til at least seven months. There are times though where I’m doing something and don’t have any hands free so she’s crying for about a minute or two until I can get to her. This isn’t damaging her is it?? I just want to make sure that isn’t cio method. I try to get to her and hold her as fast as I can. Thanks!