You follow the trend of your university.

You may put at the end of book as appendix or other ways or as suggested by publishers.

Mostly in the appendix after the reference section.

Thanks all for your suggesions.

Adding supplements in the appendix looks correct.

May be one problem with puting supplements in appendice is abot text supplements. In most cases appendices are tables/figures...

If the paper of the supplements us published, in stead of appendices, citing the published paper is a good option.