The tram & bus lines in Flanders are operated bij De Lijn. It’s advised to buy your tickets in presale at trainstations, grocery storeand are valid for 60minutes. Within this time period you can change lines unlimited. After the 60 minutes you can continue your ride towards your destination. If you need to change lines again, you need to buy a new ticket.
Daypasses cost 6€ in presale and are available at Railway Stations, news paper stalls and grocery stores. When you buy them on the bus or tram, you’ll pay 8€.
Routeplanner De Lijn: https://www.delijn.be/nl/routeplanner/