Once you are logged in you will have access to the members listing from your dashboard. Navigate to the members page and find the member you wish to pay and click on there name. You will now be brought to the members profile.
On the right of the members profile you will see an area to "Start a Transaction with Member"
Fill in what you are paying for, choose "Pay" from transaction type menu and choose how much you are paying the member.
Click Submit and your payment has been made to that member. Your account will be deducted, and the payee's account will be credited.