On this system there seem to be multiple copies of Skype - the one I installed and use all the time, something called Skype Wifi and one which was preinstalled with Win10 which seems to be for business use and which I couldn't get to work for me.
So, on the version I use all the time, just below my name there are 4 icons labelled Chats, Calls, Contacts and Notifications. If I click on the Contacts icon, it switches to a list of all my contacts. Just above that list is a bar labelled New Contact.
Click on the New Contact and a box pops up to add a new contact. At the top is a box (blue on my system) with the words Find People in it and the cursor already there. Eneter your MD's email address in there, and if he/she is has a Skype account with that email address it will show up under the box. You then click on the Add button to the right of their name to add them to your contacts.
If they don't show up from the search, you will see an Invite Friends option below the search box. Click on that and you will be shown a couple of options to invite them to contact you on Skype. One is a link which they can use to do so on the web (but they have to be using Chrome or MS Edge as it doesn't work for Firefox). The other there is an option to send them an email invitation to join Skype.
Hope that helps.