How to implement auto incremental field?

Hello,

I want to create a field in which values automatically inserted in sequence numbering and always unique. I have gone through several articles and I found that there are several ways to archive it. I wanted to go for plugin way. I tried to import below two plugins to my dynamics 365 online environment.

1 crmnumbering.codeplex.com

2 https://advcrm2011autonumber.codeplex.com/

but in both the case I am getting error like this while importing solution  - https://www.screencast.com/t/aIVSRtqHwjl

I tried various solution to fix it but not succeeded, is there any better solution to achieving auto numbering field?

Regards,

Ashish