Evidence support of stepchildren N-400

Hi all,

My husband and I are applying for the citizenship for being lawful permanent resident for at least 5 years. My husband was married before we got married and he has 2 daughters 22 and 18 years old. On my aplication I put on my list my 2 children that we have under our marriage and also the 2 stepdaughters who are living in Mexico with her mom. My husband is paying child support monthly. In my application under evidence I asked for child support but I don’t give any support to my stepdaughters but my husband. My question are:
What kind of evidence do I need to attach on this part.
My husband have the bank statements where he is paying child support . Do I need to send this statements , since when ? 5 years ago ?

Thank you all .