Great Intro there. Carpentry is not an easy hobby to pursue, the wood blocks I destroyed 20 years back in the college carpentry workshop still haunt me.
Child seats, I am a current owner of one. For my first kid, I chose from the finest in the grand aisles of Babies"R"Us. But with the second kid, it was slim pickings in the limited baby shops in Bangalore.
But it is good know some basics when you venture into Bangalore baby shops. The sales men/women you encounter would have never used one to know any better.
1) Pick a seat whose cloth material can be easily removed for washing. The seat can get very dirty in local weather. You wouldn't want to put your bundle of joy in dirty seat.
2) All buckles should be made of metal. Plastic buckles may look cute, but it is said that the buckles experience most stress during an accident. The plastic buckle will simply give up.
In India I haven't come across infant child seat, therefore you may want to wait and purchase the 4+ month baby seat.