magento 2 , need to fix issues with payment option

i am having 2 payment gateway option , one is ccavenue, in which customer must redirect to success page, and must get order mail confirmation from website,at present after making payment , customer is redirected to home page, and also not getting order confirmation mail from website, i need this to be fixed , Secondly , in razor pay customer must be redirected to payment page, so that we can get order details in our admin, and once paid, they can be redirected to success page, and get order confirmation mail, at present customer is being asked to fill payment details on checkout page itself if they select razor pay, they are not directed to razor pay page, and incase of payment failure, we are not getting any order details on payment page, due to which we are not able to follow up also with the customer