Regarding when and how to make up for missed prayer, we would like to cite an explanation given by Dr. Rajab AbuMleeh, Ph. D. in sharia on a similar issue where he stated:

“You can perform it at any place and at any time. As for the issue of Qiblah, you are not obliged to repeat your previous Prayers after knowing the new Qiblah as long as you did your best to decide its direction.”  Elaborating much on this issue, Sheikh Ahmad Kutty, an Islamic scholar  stated:

Salah is the most important pillar of Islam. It is in fact the first religious duty prescribed on every single prophet from Adam to Muhammad, second only to testifying the Oneness of Allah. Allah says, Salah, indeed, is a duty enjoined upon the faithful at the appointed times.” (An-Nisa’: 103). The Prophet (peace and blessings be upon him) further narrates in a hadith Qudsi: Allah said: “The covenant between Us and them (i.e., the disbelievers) is Salah; so whoever establishes it establishes religion; whoever undermines it undermines religion.” (Sunna al-Tirmidhi and Nasa’i)

It is therefore important that we never become slack in performing salah; if we miss any salah for whatever reason, we must pray it immediately without further delay. The Prophet (peace and blessings be upon him) said, “Whoever oversleeps and misses his prayer or forgets to do it, let him pray as soon as he remembers it.” (Sunan al-Nasa’i)

In light of these and other evidence, the vast majority of scholars and imams are of the opinion that one must make up for all of the prayers one has missed in life, no matter how many they are. So according to them, you should make up for all of these prayers. One of the best ways to do this—as has been suggested by one scholar—is to pray with each fard that you perform another fard in lieu of what you missed in the past. Thus, for instance, before or after praying Zuhr, pray another four rak`ahs of Zuhr as qadha’, and pray another four rak`ahs of `Asr every time you pray `Asr; you should continue to do this until such time that you can be pretty sure that you have made up for all of the missed prayers.”