Since your employee is working from home, he will not always be comfortable with internal tools. They will be new to him. Take the time, for example during a meeting, to make sure that they have all the necessary equipment to work at home: a professional computer, a professional telephone.
Make sure that they have a quiet place to work and a reliable internet connection. This is important because it will show your new employee that you care about their well-being, even if you are not in the same office.
Show them the different internal software that you use so that they can get familiar with it as soon as possible.
Finally, remind your new recruit of your IT policy to avoid potential mistakes.