Trying to install contact-group-excel-paste plugin on rainloop : fail

[mariegwo]

Rainloop webmail 1.17.0 installed on a subdomain (o2switch host)

I want to create lists of contacts, and i found info here to install contact-group-excel-paste to make it work but I'm not sure I did that well as I'm a newbie on this...

I created the folders with ftp access : mydomain.com/rainloop/data/data/default/plugins/contact-group-excel-paste (all in italics didn't exist)
I downloaded the files from https://git.pofilo.fr/mirrors/rainloop-webmail/src/branch/master/plugins/contact-group-excel-paste and added them in this folder.
I'm trying to add a contact with several email addresses and when I try to send an email to this "list", it doesn't work.

Can someone help me ?
Thanks a lot !