With difficulty! They will never be as good with computers as you are. You just need to accept that.
It is probably not a good idea to try to teach them competencies they do not see the need for. You could help them understand how to do things that they want to do. With that motivation they might be better able to concentrate on the essentials.
People have specific learning styles. When the teacher prefers a different modality to the learner you have a huge obstacle to overcome and often times neither is aware of it. The modalities are often described as: visual; auditory; kinesthetic. There is a massive body of literature on this area. For example; "SuperLearning".
In very brief summary the options are:
1. Show them how to do things and let them take notes or even record a short video on a smartphone.
2. Let them sit at the computer and tell them what steps to take. Again letting them take notes might help.
3. Document the steps required, e.g. screen grabs, and written explanations. Then let them follow those instructions as and when they need to refer to them.