I am installing a ceiling fan, but there is a red wire , a green wire a white wire and 3 black wires... help

The red wire tells me there may be a second switch controlling this ceiling box, look for it. Test the wires with a meter but the green should be ground, white neutral and blacks are hot with switch thrown, red is likely hot too but not unless you flip that second switch. Tell us about the fan wires and if there is a light kit. Do you plan on a remote?