Why is it important to be familiar with the laboratory apparatus and their uses?
If you do not use instruments or lab apparatuses correctly (or use an apparatus for something it is not planned for) you can very seriously injure yourself!
In addition, if you misuse instruments used for measurements, the results of your experiments will be wrong due to you will not have correctly measured the thing you were trying to verify, and so you will draw the wrong conclusion about the result of the experiment.