Shiva Purana
शिष्यासनं सम्प्रपूज्य षडुत्थापनमार्गतः ॥ शिवासनं च संकल्प्य शिवमूर्तिं प्रकल्पयेत् ॥ ३७ ॥
He shall worship the seat, of the disciple with the rite of “Ṣaḍutthāpana.” After conceiving Śiva’s seat he shall install an idol of Śiva.
english translation
ziSyAsanaM samprapUjya SaDutthApanamArgataH ॥ zivAsanaM ca saMkalpya zivamUrtiM prakalpayet ॥ 37 ॥
hk transliteration by Sanscript