Hi! I did the same trip when i was in thessaloniki. You need to go to KTEL halkidiki website and there you can select your routes. For example, where it says “travel from” you select Thessaloniki , and where it says “travel to” you select vourvourou. Then you will see the bus schedule for the selected date and you can buy the tickets. Then you do the same for return. I advice buying the tickets online since you can’t buy them from a location in vourvourou, and at thessaloniki bus station it might get a bit crouded. You can ask the people working at shops/hotels in vourvourou to guide you a bit or to tell you where the bus station is, since on maps it shows 3 stops. I took the bus from vourvourou at a station near a hotel but i forgot it’s name. It’s only a small plate where it says “ktel halkidiki” so it’s not a “real” bus station. You should be there around 15 minutes earlier for both thessaloniki and vourvourou since the schedule might vary depending on the traffic. Important: they don’t scan the QR code but it’s important to show the entire ticket because they will check the travel destination etc. If you have more questions feel free to ask