How did Einstein derive general relativity (GR)?

Did he use: the equivalence principle? The principle of least action? Anything else?

Note, I'm not looking for a full mathematical derivation of GR! But rather, I'd like to know what Einstein's starting points were.

Note: I found a similar question that has been asked already, but I couldn't find an answer to my question in the answers.

How did Einstein derive general relativity (GR)?

Did he use: the equivalence principle? The principle of least action? Anything else?

Note, I'm not looking for a full mathematical derivation of GR! But rather, I'd like to know what Einstein's starting points were.

Note: I found a similar question that has been asked already, but I couldn't find an answer to my question in the answers.

How did Einstein derive general relativity?

Did he use: the equivalence principle? the principle of least action? anything else?

Note, I'm not looking for a full mathematical derivation of GR! But rather, I'd like to know what Einstein's starting points were.

Thanks!

Note: I found a similar question that has been asked already, but I couldn't find an answer to my question in the answers.

How did Einstein derive general relativity (GR)?

Did he use: the equivalence principle? The principle of least action? Anything else?

Note, I'm not looking for a full mathematical derivation of GR! But rather, I'd like to know what Einstein's starting points were.

Note: I found a similar question that has been asked already, but I couldn't find an answer to my question in the answers.