Step::1 Login to your Redserverhost Client area.
Step::2 Now click over the Billing section and choose My Invoices option.
Step::3 Next click over the unpaid invoice to open.
Step::4 In the Payment method drop-down box select the payment method as per your convenience.
Step::5 Finally click over Pay Now button, it will redirect you to the Payment gateway page.
That's It !Go through the video tutorial to get the procedure in detail. You may read the blog as well.