The first Maṇḍapa is the abode of Mūlamāyā (primary delusion) and is very auspicious and stationed there itself. Beyond that is the sanctum sanctorum, the auspicious place of the phallic form of Śiva.
एवं गुरुक्रमाल्लब्धं नंदीशाच्च मया पुनः । ततः परं स्वसंवेद्यं शिवे नैवानुभावितम् ११९ ।
This knowledge has come down from the preceptors. I got it from Nandīśa. Beyond this, it must be inferred from it and it is actually experienced only by Śiva.