I hope someone can help me.

I do not understand how to calculate log odds. I know how to calculate odds and proportions and I understand what differ between them. I just do not know how we get the log odds.

Log odds are supposed to help us since it can treat any value between - ∞ and + ∞ . Moreover, they can be useful when proportions are not symmetric. But I just do not know how to get them.

I just do not understand the formula:

Thank you for your time