1. Down payment is made to the builder to confirm the purchase decision. It typically represents a percentage of the full purchase price. It could be non-refundable if the deal falls through.

2. The sale deed is the agreement between the seller and the buyer and is proof of transfer of property to the buyer. It is signed by both the parties and also by a minimum of two witnesses along with all their details.

3. Stamp duty is the tax levied by the state government on the agreement value or the market value, whichever is higher. It is payable by the purchaser and may vary across states.

4. It is only after the payment of stamp duty that the sale deed is considered legally valid and can be admitted as evidence of transfer of property in courts. The sale deed has to be registered with the sub-registrar of the jurisdiction where the property is located.

5. The registration fee is paid for getting the sale deed registered and is associated with getting the property transferred in the name of the buyer. The original document, along with two photocopies, has to be submitted and registration requires two witnesses.