What do tour to and tour of mean? Are they right or wrong?

Be on a tour of is generally used to mean "on a journey of...".

Tour is a trip similar to traveling around or sightseeing, such as tour of London , tour of World, the general phrase is on the tour of some place

tour to means "on the journey to..." The preposition to generally contains the meaning of going to a certain destination.

So depending on where it is used, it is correct. Generally speaking, the meaning is not very different.