First of all you need to register on site:
When you finished, under your account you will see menu My Wallet:
Choose Wallet Topup
Under that menu you`ll see this:
Choose amount of money you want to spend on your purchase and press Add
In next window you`ll see all available payment systems:
Choose which ones are suitable for you and/or your country (not all pay,ent can be processed from some countries)
When you`ll finish with Wallet topup, you can go to Shop? add products to Cart and pay for them from your Wallet.
Presets and some information from secret chat available too.