Kothapet first home: Hidden costs and agreement confusion

Kothapet area mein Salarpuria Sattva ka project dekh raha tha. Site visit pe gaya toh bas show flat dikhate hain, but builder-buyer agreement mein kya red flags dekhun, samajh nahi aa raha. Nobody tells you this stuff beforehand. EMI ke alawa kitna extra kharcha expect karun? Stamp duty, registration, interiors ka budget... pura process kitna costly ho jata hai. Koi tips hain kya ki kya kya check karun aur kitna buffer rakhun? First-time buyer hoon, thoda nervous bhi.