Tenant hasn't returned my calls/ Did not pay rent

[Cameron Green]

I'm currently managing my first rental property in Cleveland, OH and found what i thought to be a great tenant. He pay the first few months rent fine using apartments.com, but has not paid this month. I texted him and called him to see if everything was okay and if he was having any trouble paying. He did not answer my text or my phone call. He does have a 5 day grace period before the rent is considered late. If he doesn't pay after the 5 days or if I don't hear from him what should my next steps be? I plan on emailing him and gaining a larger paper trail. when do I serve a notice and how much time do you think I should give him?