I am able to view my files from my hub in Hub Brower and load my model from the items now I want to add new model in the project through Hub Browser.
I am not sure what process and API calls should be used to achieve this.
uploading a file to BIM360 using APIs involves multiple steps, this is the latest step-by-step tutorial from our documentation. This sample has the option to upload a file and here's the source code.