Sounds like no operating system is installed on there. You will need to create installation media using the 'windows media creation tool'

You can download it from here:

https://www.microsoft.com/en-au/software...

You will need an 8GB flash drive and another computer to set up the flash drive for Windows 10 installer.

And hopefully the mSATA SSD installed inside the Surface has not gone faulty as that is a PITA to replace, really hard to separate the screen without damaging / cracking it.