Cannot Download Kodi on M8 box

1st of all I am a novice and was trying to follow instruction on Youtube.

I had an older version of Kodi (14.1 I think) and wanted to upgrade. I uninstalled the older Kodi. I downloaded the Android “ARMV7A and ARMV8A” from the Release version. I downloaded both versions. I did this from the browser and also tried it off a USB stick. When I try to install it, I get a error message something about “not the right PAK” or something to that effect. I can post actual message if you need it. Can you help?

I do have an older download of 15.1 version as well. I CAN install that but not sure how to get all the add on there.

Please help! Thanks!!