Boot MacBoot Pro to internet recovery and external display

You should be able to connect an external monitor. Your computer has a Mini-DisplayPort (looks like TB2) that can be used to connect to an external monitor. But without an internal display you may have difficulty setting it up. If you do then you need to do the following:

Internet/Network Recovery of El Capitan or Later on a Clean Disk

     If possible back up your files before proceeding.

1. Restart the computer. Immediately after the chime hold down the (Command-Option-R) keys until a globe appears.
2. The Utility Menu will appear in from 5-20 minutes. Be patient.
3. Select Disk Utility and click on the Continue button.
4. When Disk Utility loads select the target drive (will be the out-dented entry) from the side list.
5. Click on the Erase tab in Disk Utility's main window. A panel will drop down.
6. Set the partition scheme to GUID.
7. Set the Format type to APFS (SSDs only) or Mac OS Extended (Journaled.)
8. Click on the Apply button, then click on the Done button when it activates.
9. Quit Disk Utility and return to the Utility Menu.
10. Select Install OS X and click on the Continue button.

This should install the same version of macOS that you had installed. The drive will be erased.

What is the exact model that you have? To find the model identifier open System Profiler in the Utilities' folder. It's displayed in the panel on the right. You may also find the complete model information by selecting About This Mac from the Apple menu.

Need to know if you can even do a network recovery. However, if you cannot get video on an external monitor, then you have a bigger problem to solve.