All the duties such as waking up, sandhyavandanam, going to sleep in the night, etc. that one does every day are nitya karmaanusthaanam. One can learn about these from texts such as Ahnikam.
Notes:
Let us look briefly at the duties that must be carried out every day.
The daily ritual begins with meditating upon Hari while waking up. After taking bath, one must adorn urdhva pundaram and perform Sandhyavandanam and other duties.
A bachelor who has undergone upanayanam, must do samitaadhanam; if one is a married male, must perform aupaasanam and devarishi, kaandarishi, pitru thrapanams. Those who have undergone upadesam, must also perform aadharasakthi tharpanam, brahma yagyam, maadhyaanikam, nityaaraadhanam, and anuyagam (partaking of the prasadam offered to Perumal).
For self-study, one must read books that advance thoughts of the Lord. Earning the materials needed for Tiruaradhanam, retiring for sleep with the thought of Bhagavan, etc., are all considered nitya karmaanushthaanam.