Install Kodi

Greetings,
I am completely new to Android and Kodi. I purchased a Henscoqi M9X III Media Box with Android 6.0.1. I suspect these Android TV boxes built in China all come from the same factory and resellers just put their company name on the shipping box and don’t provide any consumer support. But this Kodi.tv site looks like my best bet to obtaining help. I am surprised this type of box doesn’t come loaded with the latest stable version of software, but with development versions, but what do I know? I have a lot to learn about Android & Kodi.

The Box came with Kodi 17.0 Alpha 3 installed. I want to install the current available Kodi 17.0 Beta 6. I used the Box’s web browser to download the Kodi 17.0 Beta 6 from Kodi.tv – but that resulted in three files, named:

Code:
kodi-17.0-Krypton_beta6-arm64-v8a-1.apk  
kodi-17.0-Krypton_beta6-arm64-v8a-2.apk  
kodi-17.0-Krypton_beta6-arm64-v8a.apk

Instructions I have found don’t account for there being three files – so my question to you is: which do I install, or do I install all three and if so, in which order? Thanks in advance.