They are just different ways of drawing the same compound, the following pair are diastereomers.
The given pair of compounds are not constitutional isomers, because constitutional isomers have the same molecular formula but different bond connectivity. But the given pair have the same bond connectivity.
The given pair of compounds are stereoisomers because they have the same molecular formula but the 3D space arrangement is different. And finally, the given compounds are not mirroring images of each other so we call them diastereomers, not enantiomers. As enantiomers are superimposable mirror images of each other. The structures of the given pair of compounds are attached as a picture.
You can also learn about diastereomers from the following question:
https://brainly.com/question/21506956
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