How to install Kodi and which version

I just bought an Easytone Android tv box with remote and mini keyboard. it was supposed to be fully loaded whatever that means. It wasn’t working so I did a backup and reset. Now when I try to go to Kodi.tv to download kodi 16.1 Jarvis it says there are issues with the certificate. When I viewed it it said the date was incorrect. How do I install Kodi on this box so I can watch movies. Also I can’t seem to set the time and date. I do it but the next time I turn it on it’s all screwed up again. I really need some guidance. A 69 year old Grandma. Any help greatly appreciated or direct me to the information. Thanks