Recognizing Objective morality is the first step towards enlightenment, so for getting that far already I wanted to say congradulations.
What is 'right' or 'good' or 'moral' has to be true at every level. It must be good for you, and your spouse, and your family, and your community, and your nation, and all nations. There is no such thing as 'ends justify the means' and there is no such thing as subjective morality. If you accept those premise, then you are already past 80% of the world's population on your path to finding this base.
In terms of what this moral base is, there's tens of thousands of years of literature on this... but all you have to do is look up (in a metaphysical sense). What is a 'good' about yourself? Foster it. Then what is good that is greater than yourself? Seek it. Then if you find something greater still, seek that instead. And again, and again. If you can imagine a theoretical 'good' that is so universal, so true, so epic in its scale that it encapsulates all morality, then you've found it. Ancient traditions called that God.
The beauty of this process though is you don't have to believe in God for this to work (though it often leads there). Great places to start could include John Lock's Social Contract, Heinlien's Stranger in a Strange Land, of the Eye of Shiva (tried to give a nice spread there because idk your culture).