enter with the right foot is a popular expression of the Portuguese language and means "get in well or start something well".
"Get in on the right foot" is not just an expression. For many people it is a ritual, a superstition. It is possible to verify this in the case of football players. Many enter the pitch on the right foot, hoping that luck plays for their team. Some students also enter the classroom on the right foot, so the material doesn't slip out of their minds before an exam. - "I have to enter the room on the right foot, otherwise I won't do well in the test!"
expression source
The term "entering on the right foot" arose out of the superstition of entering somewhere on the right foot for luck. This tradition is of Roman origin. At events and parties in Rome, the hosts believed that by entering on the right foot, they could avoid any omens at their party and therefore asked their guests to comply with this standard. In Latin, the word “left” means “sinister”, which explains the Romans' belief that the right and left sides symbolized good and evil. It was from that point on that expression and belief spread throughout the world.
This belief is so well-founded in our society that Santos Dumont himself had stairs built in his house where it was only possible to climb by starting the path with the right foot. Until today the "Santos Dumont ladder" is manufactured.