What is a one-sentence summary of the following article?
Click the chat that you want to into a group chat on the left side of the Skype window. If you haven't yet created a chat, create one first. This person-shaped icon with a "+" in it is in the upper-right side of the chat. Doing so opens an "Add participants" window with all of your Skype contacts listed in it. Click the checkbox to the left of each contact whom you want to add to the group. You can also search in the text box at the top of the "Add participants" window for a contact to add if you want to add someone not in your contacts. It's a blue button at the bottom of the "Add participants" window. Doing so will create a new chat with your group of contacts.

Summary:
Select a chat. Click the "Create group" icon. Select contacts. Click Create Group.