This category of relative is called immediate relative since the visa is immediately available to them, they dont have to wait in line to get their visa. In fact after your application have been submitted you should get your answer in couple of month , most of the time the whole process is completed in less of a year if you promptly answer all the request from NVC. Remember you will need to complete a separate form I-130 for your spouse and child if you are A US citizen. However YOu don"t need to file a separate I-130 for your grandchild or the spouse of your child they will come as a derivative but you are required to mention their name on the form I-130
to help your spouse or unmarried Child under 21 get a green card you are required to file the form I-130 click on the link form I-130 on your right side to find out how you can get access to the tutorial related to this form