If you answer everything accurately you should have no problems, the questions should be self-explanatory.
If you have custody less than half the nights of the year, indicate this with "5 months" or less as the estimate for how long the child lived with you, and then answer "no" that you do not have a custody agreement that allows you to claim the child this year.
If you have custody more than half the nights, pick "7 months" or longer, and then answer "yes" there is a custody agreement that allows the other parent to claim the child this year. The child will not be your dependent, but will still allow you to file as head of household, or claim EITC or the Child Care Credit, because those benefits always go the parent with physical custody more than half the year and can't be waived, transferred or shared. You will also be prompted to print a form 8332, which you must sign and give to the other parent so they can legally claim the child.
