The first step is in getting the actions right. So practise all movements slowly. Pay attention to the movements, the little actions, all the details. Make sure you know what you are supposed to do, what you are doing, and make sure they are the same. This step is about knowing the form.
Next is learning how to use your kua to move. Again, practise slowly, focusing on using your kua to move your body and your arms. This step is about meeting the principles of taiji.
Once you can use your kua, next comes varying the speed of movements. This is when you use your kua to vary the speeds of your movements, to give the fast-and-slow rhythm that characterises Chen style taiji. This step is about manifesting the flavour of Chen style taiji.
Finally, as you practise your Chen style taiji routine, visualise the application of each movement. This final step is about learning how to apply taiji.