Setting up of partial payment is quite easy. You have to install the addon (Yatra Partial Payment with Yatra plugin ) and then just navigate it to Yatra -> Settings -> Payment Gateways, then you will see following settings there.
Enable Partial Payment: You can enable/disable partial payment. By default this feature is disabled. So you have to enabled it to setup partial payment.
First Payment Amount (%): You can setup upto 0 to 100 there. It means user can pay ( deposit ) any percentage of the cart amount while booking the tour packages or user can pay full amount. As per this screenshot user have to pay ( deposit ) 23% of total cart amount to book the tour packages and remaining can be paid later via their my account section or they can pay full amount of the cart.
Front View of Partial Payment: