"most stars in our part of the galaxy are formed":
in open clusters of a few dozen.
alone.
in globular clusters of millions of stars.
in a singular event just after the big bang.
in associations of thousands of stars across a spiral arm of the galaxy.

Most stars in our part of the Galaxy are formed in open clusters of a few dozen alone.

Explanation:

Stars are those objects in the galaxy which are formed up of plasma consisting of  gases mostly hydrogen and helium. They are luminous balls that can been seen easily if we look over the sky in the night. The nearest star to our planet is Sun. Fusion reaction take place in sun that emit out a lot of energy and convert the hydrogen in helium.

Interesting Information:

It has been observed that the stars that are in a cluster have the similar composition and age. They are also present at the same distance.