How do you do flip chair conformations?

There is no substitute for a model.

When you flip a chair conformer of a 6-membered ring, each equatorial substituent becomes axial, and each axial substituent becomes equatorial. This being said there is absolutely no substitute for making a model with a molecular model set. Now, not only do you have to make the model, you also have to be able to represent the conformer on paper. This is non-trivial and takes practice. Model sets are always permitted in exams.