Turn PC into wireless display

1. Open the action center. (It's represented by the speech bubble icon in the lower right corner of the screen.) 

2. Click Connect.

3. Click Projecting to this PC. (A settings window will appear.)

4. Select "Available Everywhere" or "Available everywhere on secure networks" from the top pulldown menu. 

5. Select "First time only" or "Every time a connection is requested" under "Ask to project to this PC." I recommend picking "First time only," unless you're really worried that some rogue thief is going to grab your phone and project to your computer without your permission. 

I also recommend leaving "Require PIN for pairing" off since you have to grant permission on the receiving computer anyway. You can also decide whether you want your PC to receive projection requests only when it's plugged in.

6. Click Yes when Windows 10 alerts you that another device wants to project to your computer.

The Windows Connect app will launch in its own window. You can drag, resize or maximize the window.