You recieve the Paypal adress through Owen's pms, you go to 'Send Money' and from there you paste the adress in, you chose the amount of money you'd like to pay, in this case it's 30.
you type 30 in the little box and you select what currency from the dropdown box, after that you simply chose 'USD' and just scroll to the bottom of the page and confirm the payment/transfer-
You tell Owen that you have paid and he will confirm the donation, after that you will probably go ingame with Compton and park your cars where you'd like them to spawn, same goes for your house, and if you wish to map(I think you're talking about gold?), you simply map and send the .map file to Compton and he adds it to the gamemode.
I hope this helped you, if not just shoot me a pm and I'll be glad to help you out.
Thanks.
(Check the spoiler for further instructions with pictures.)
- Spoiler: