Siman 661
Presented here for study, not as a practical ruling. The Shulchan Aruch rules by Sephardi custom, the Rema's glosses by Ashkenazi custom, and the Kitzur follows Ashkenazi custom. For a practical question, ask your rabbi.
א בְּלֵיל יוֹם טוֹב שֵׁנִי אוֹמֵר קִדּוּשׁ, וּזְמַן אַחֲרָיו מִיָּד, וְאַחַר כָּךְ בִּרְכַּת סֻכָּה. (זוֹ דַּעַת הָרֹא"שׁ וְכֵן רָאוּי לִנְהֹג).
1 On the second night, we say Kiddush and Shehecheyanu immediately afterward, followed by the blessing over the sukkah. (This is the opinion of the Ros"h, and it is fitting to do this.)