In between the old testament and new testament there is a 400 year period called the intertestamental period. The 400 years of silence.
During this period the rabbis were debating some of the weirdness happening in the old testament. We have an invisible god no one can see but for some reason people meet and talk with him. Sometimes god refers to himself in the plural. Sometimes lord refers to god in the second person. Sometimes god is one, sometimes he is more than a single being. Sometimes a figure called the angel of Lord or word of Lord speaks as god.
When you read the new testament and know your old testament it becomes pretty obvious who the authors think Jesus is. He is the visible image of the invisible god. Know one has seen god, Only the son etc etc.
How it all works ? Who knows. Bible isn't entirely clear but it is pretty on who the authors think Jesus is.