You can see statistics on 3 different places
First one is User overview - here you can see list of users that register via your link. You can see registration date, what link was used for registration and number of payments.
Second one is Users payments - here you can see when some user made payment and when he did it.
Third is Manage links - here you can see detailed statistics of your links. You can see how many your links have clicks, registration and payments. You can also choose which filters a user gets after registering.