Salaah

How should one reply to the Azaan if one forgot to reply from the beginning?

Q: If a person did not repeat the words of the Azaan immediately after the muazzin but only remembered at the end of the azaan at the time when the muazzin reached Hayya Alal Falaah, can he repeat the words from the beginning of the azaan or he should only repeat the words of the muazzin from hayya alal falaah?

Question relating to Qadha Salaah

Q:

  1. What is the procedure of doing missed Qada namaz of last 10 years, approximately 500 salaahs?
  2. What will be intention?
  3. How many Rakat for each salat?
  4. Is there qada for witr?
  5. As I have lots of missed namaz, can I do qada salat instead of doing any nawafil as well tahajud? Please explain in detail so that I can do it.