The board's name is NUC5CPYB. The system's (kit's) name is NUC5CPYH. The "H" in this name is an indication that you have the style of chassis that provides a bay into which you can install a 2.5" SSD/HDD drive.
What you want to do is go to the download page for the NUC5CPYH (or B; gets you to same place) and download the latest BIOS file. Based upon what I am seeing on the download page right now, It will be the file named PY0043.BIO. Place this file in the root folder of a formatted USB flash stick (key) and insert this flash stick into one of the NUC's USB ports. Power on the NUC and keep pressing the F7 key until it presents a dialog allowing you to choose the BIOS file to install. Select the one you put on and go. It should install without issue...