Start by Marrying a Wife and Create an Eternal Clan of Immortals

Realm divisions: Qi refining, foundation building, elixir formation, Nascent Soul, spirit transformation, void refining, body integration, Mahayana (supreme), transcending tribulation (emperor realm). Each realm is divided into ten small realms, but the division will not be so clear in the book. It will be divided into early stage, middle stage, late stage and perfection. So when you see the terms such as the early stage of foundation building and the peak of foundation building, you don't have to worry about it. That is the third level of foundation building.