SCHEDULE AL in case of joint property

Le'ts say we have a property of 10 lakhs. A and B are sibling. A is salaried person with more than 50 Lakhs income. B is currently studying and have no source of income. A bought the property and paid whole amount. B is also co-owner of the property with 50 percent share in the final registry of the property. A and B both have 50-50 ownership. Basically A is gifting 50 percent of property to B. Here are the questions - 1. How much A needs to decalre in the "Schedule AL" ? 50 percent or 100 percent ? - I believe 50 percent since A is owner of 50 percent . 2. If we sell the property, what will happen with capital gain? A needs to pay taxes for the 50 percent capital gain and B needs to pay for remaining 50 percent capital gain. Is my understnading correct?