Install this file: manaplus-addrepo_1.0_all.deb

For linux Mint install this file: manaplus-addrepo_1.1_all.deb

Run in terminal:

sudo aptitude update
sudo aptitude install manaplus

or

sudo apt-get update
sudo apt-get install manaplus

or select and install in synaptic package manaplus

See also: Ubuntu & Debian repository, screenshots

Debian, Ubuntu