How does an individual worshipper, who was late in performing the 'Isha prayer, make up two rak'ahs of Tarawih prayer that he missed?

Firstly: If you miss the 'Isha prayer and the Imam is praying Tarawih, it is preferable to join him with the intention of praying 'Isha. When the Imam says the taslim, you complete your prayer. Do not pray alone to avoid causing disruption.

Secondly: As for the Tarawih prayers you missed, if you wish to make them up, then make your Witr an even number of rak'ahs with the Imam (by adding one rak'ah after the Imam says the taslim for Witr), then pray the Tarawih rak'ahs you missed, and then pray Witr. Imam Ahmad and Ibn Taymiyah have stated the permissibility of a person praying a fard (obligatory) prayer behind someone praying a nafl (voluntary) prayer. It is best to make up what was missed in congregation if possible; otherwise, pray it individually.