For models with other architectures, such as Qwen family, how to find the best `\alpha`, `\beta` and `\sqrt{1/t}` parameters?

The author mentioned in the paper that for the Llama family, the good values ​​of `\alpha` and `\beta` are `1` and `32`, but did not mention how to obtain these two parameters. In addition, the author mentioned that `\sqrt{1/t}` can be fitted by the lowest ppl. Can this part be explained more clearly?

If anyone can answer my question I would appreciate it!