After sending the trade request you get the payment details.
Trader may not publish the payment details directly and asks
you to contact to get the exact account name needed for the payment.
In this case, send a LocalBitcoins.com message to the the trader and ask for the further details.
When buying bitcoins online,
the payment window is 90 minutes, but this may vary depending on the payment method
and the terms of the trade.
If you need help on how to make the payment use LocalBitcoins.com messaging to discuss with the trader how to make the payment.