If a person has missed several salaats and decides to make qada of them, he should specify the time of the salaat when making his intention. That is, he should make intention in this way: I am offering the fard of fajr salaat. If it is the qada of zuhr, then he should say: I am offering the fard of zuhr salaat. In the same way, he should make the intention of whichever salaat he wishes to make qada of. If in his intention he merely said: I am offering qada salaat, and did not specify which salaat it is, then this qada will not be valid. It will have to be repeated.
If salaat of several days has been missed, one should also specify the day and date when making the intention. For example, a person missed the salaats of Saturday, Sunday, Monday and Tuesday. When making his intention it will not be proper for him to merely say that he is making qada of fajrsalaat. Instead he will have to make intention in the following way: I am making qada for the fajr salaat of Saturday. When zuhr time comes, he must say: I am making qada for the zuhr salaat of Saturday. In this way he should continue making intention. Once he completes making the qada of all the salaats of Saturday, he should say: I am making the qada for the fajr salaat of Sunday. In this way he should offer all his qada salaats. If he is making qada for several months or years, he should also specify the month and year and say: I am offering the qada of fajr salaat of a particular day in a particular month and in a particular year. Without saying it in this way, the intention will not be correct.
If a person does not remember the date, month or year, he should make his intention as follows: Of all the fajr salaats that I have to make qada of, I am making qada of the first one that I had missed, or, of all the zuhr salaats that I have to make qada of, I am making qada of the first one that I had missed. He should make his intention in this way and continue offering his qada salaat. Once the heart is satisfied that qada of all the missed salaats has been made, he can stop offering qada salaat.