Kailash Nath Projects: Under-construction lena sahi hai?

Okay I'll be honest — I completely underestimated how confusing this process is. New Delhi mein first-time property dekh raha hoon, Pocket 3 mein Kailash Nath Projects ka ek under-construction flat pasand aaya hai. Builder ka delivery track record kaisa hai? Under-construction lena kitna risky hai, yaar? Property price ke alawa aur kya kya kharcha aata hai, like stamp duty, registration ke upar? Legal verification (title search, RERA) kaise karte hain? Bahut confused hoon. Any advice on these points?