The heat is not working in my 2005 Kia amanti. It blows cold air period

First - check coolant level when engine is COLD .. Cooling system 'must' be full before heater will work properly .. IF coolant level is ok .. Seek hands-on help from qualified personnel - checking coolant level is about all the average DIYer needs to attempt.

This could be an issue with a blend air door or actuator or a stuck open thermostat. Although you would get some heat eventually with an open t-stat. I agree past low coolant its time for a shop to take a look