What is the meaning of "Al-Ba'ah"? Is it financial or physical ability and responsibility? And is the fasting mentioned in the Hadith daily, or Monday and Thursday fasting, or like the fasting of David (peace be upon him)?

The Hadith the questioner referred to is: "O assembly of youth, whoever among you can afford marriage, let him marry, for it is more effective in lowering the gaze and guarding the private parts. And whoever cannot afford it, let him fast, for it will be a shield for him." "Al-Ba'ah" (ability to afford marriage) includes both financial and physical capability for marriage. Fasting here is for recommendation, not obligation. There is no text that specifies a certain time or amount of fasting, rather it depends on the need and what curbs desire. This can be achieved by fasting virtuous days or fasting like Dawud (peace be upon him).