Hey there Mongololo,and welcome, I don't know your trike, mine is a recumbent, it's in sign -on loaded for a week's camping, a heavy load but fun to ride.
Really it's not something you can teach, but yes the general advice all ready given does hold true, if you have had a lifetime riding solos, learning to ride 3 wheels is going to be hard to learn.
Best advice I can give is o find a empty car park or quiet industrial estate, and slowly ride around, it's a natural thing to ride 2 wheels, but 3 wheels you do need to steerit where you want to go at first it will do the exact opposite to what you want, you have to counteract that.
Just sit in the middle, Steer left to go left Right to go right, on a cycle you counter steer because of road amber, if you counter steer a trike you go that direction. It's something that you need to learn slowly.
Best advice I can give is you can never master riding a trike, like you can a cycle, but you can learn to ride it.
Recumbents are far easier,butyoucab still getting wrong.
Perseverance is what you need
