Article: The Skype icon looks like a white "S" in a blue circle. You can find it on your Start menu. If you're not automatically logged in to your Skype account, sign in with your email, phone, or Skype ID, and your password. This button is located on a tabs bar in the upper-left corner of your Skype window. It will open a drop-down menu. This will open your app settings in a new window. Find the Advanced category on the left-hand side of your Options window and click it. This will expand sub-categories under it.  This box is located at the top of the Hotkeys settings. When this option is enabled, you can use keyboard shortcuts in your Skype calls. This will open a new pop-up window, and allow you to set a hotkey keyboard combination for using the Push-to-talk feature. You can select multiple keys, or assign a single key, such as ⇧ Shift, for this feature. This will save your new hotkey combination for Push-to-talk. It's located in the lower-right corner of the Options window. You can now use Push-to-talk in your Skype calls with your new hotkey combination.

What is a summary?
Open Skype on your computer. Click the Tools tab. Click Options on the Tools menu. Click Advanced on the left panel. Click Hotkeys under the Advanced category. Check the Enable hotkeys box. Check the Toggle Mute (Push-to-talk) option on the list. Select a hotkey combination for Push-to-talk. Click the blue OK button. Click the blue Save button.