Memcache and memcached on Plesk Onyx

Hello, I am a fairly beginner and need help with step by step instruction on how can I install Memcache and Memcached on my server and PHP 7.1.1.

Have desperately searched the forum and googled around, but can not find the right answer

Thanks to all who respond and help

OS:‪Debian 7.11‬
Product Plesk Onyx Version 17.0.17 Update #16, last updated on Feb 15, 2017