Generally, we perform Sandhyavandanam first and only then perform Tiruvaradhanam. However, on Alpa Dwadasi days, since we need to do Paranai (breaking the fast) very early in the morning, I request you to inform us about the correct procedure (Anushtanam) to be followed on that day.

On Alpa Dwadasi days, one must complete everything—Sandhyavandanam, Brahma Yagyam, Madhyahnikam, Tiruvaradhanam, and Vaisvadevam—before performing Paranai. Among these, if Madhyahnikam and others were performed before sunrise, they must be performed again during the Madhyahnam (noon) period. If Madhyahnikam, Brahma Yagyam, Tiruvaradhanam, etc., were performed after sunrise, there is no need to repeat them.
Shrimad Azhagiyashingar has explained this in detail in the Ahnika Grantham.