Dear Shri Sundachu,
I am giving below the Srivaishnava sampradaya with regards to Thiruvaaradanam as it's called in SV sampradayam.
To be able to perform Thiruvaaadanam, one should have undergone Samaasrayanam or panchasamskaram through an Acharya.Others can participate in the Thiruvaraadanam.
Thiruvaradanam to Salagraama perumal is performed after Maadyahnikam.This is also refered to as Ijyai There are six aasanas to be performed:
Mantraasanam(Nyasa vimsati of swami Desikan is recited)
Snaanaasanam( Thirumanjanam is performed with Purusha suktam recitation and Ghanta seva)
Alankaaraasanam and mantrapushpam (Chandanam,Doopam, deepam, pushpam, mantrapushpam-Narayana upanishad etc)
Bhojyaasanam(neivedyam,Thaligai amudu seidal)
Punarmantraasanam
Paryankaasanam
Finally one partakes Perumal theertam and distributes theertha, prasadam to all.
Regards,