hi,

jee main paper 1 exam is for admission to bachelors of technology i.e B.tech course.

jee main paper 2 exam is for candidates who aspire to study in architecture, planning domain. candidates wish to study architecture , planning  need  to appear in jee main paper 1 and jee main paper 2 both of the exams. candidates who qualify for jee main paper 1 may appear in jee main paper 2.

since your target is admission to b.tech, you have to appear in jee main paper 1 exam only.