What is conformational diastereomers how we distinguish between configurational and conformational isomers

Conformational isomers are stereoisomers that can be converted into one another by rotation around a single bond.For example, eclipsed, gauche, and anti butane are all conformational isomers of one another. ( Eclipsed means that identical groups are all directly in-line with one another, gauche means that identical groups are 60 degrees from one another, and antimeans that identical groups are 180 degrees from one another.)
These molecules can be interconverted by rotating around the central carbon single bond. For example, eclipsed butane can be made into gauche butane by rotating 60 degrees and into anti butane by rotating 180 degrees. Similarly, gauche butane can be made into anti butane by rotating 120 degrees. Because of this rotational property, eclipsed, gauche, and anti butane are conformational isomers of one another.