Sandhyavandanam (Rigveda - Smarta) by Vedabramha Sri Yoganarasimha Shastry
Sandhyavandanam is a religious practice performed by Hindu men initiated into the rite by the ceremony of Upanayanam, and instructed in its execution by a Guru (a qualified spiritual teacher). Sandhyavandanam is performed thrice daily and is accordingly known by a different name at each hour - in the morning (prātaḥsaṃdhyā), at noon (mādhyānika), and in the evening (sāyaṃsaṃdhyā). Sivaprasad Bhattacharyya defines it as the "Hindu code of liturgical prayers".
This Audio CD guides you with the Sandhyavandanam & also detailed information while performing it.