Hello Fanta
The effect you describe is called "drift" and we all have to deal with drift. You need to install a good blade first. Everyone, but everyone, on here will sing the praises of Ian John at Tuffsaws. He sells excellent blades at very reasonable prices and will give you sound advice about which blade to choosefor any particular operation.
when you have the appropriate blade, it should be installed on the wheels so that it runs on the wheels in such a position that the teeth cuts parallel. There is a knob on the back to alter the tracking.
The blade guides should just clear the teeth but support the body of the blade
It's not difficult but you do have to get it just right, by doing the right things in the right order.
There are a couple of good books on bandsaws, Dukinski and Bird. Both American. There are a couple of British offerings on DVD, my own and one by Alan Holtham. There is a lot of free info on YT, mostly American and of mixed quality. European bandsaw tables are not as easy to shift over as on the smaller American machines that are depicted.
You are at the beginning of a learning curve here, but once you have the hang of it, you will have a very useful workshop machine.