Installation problem Linux Mint 18

1

I am trying to install LibreTime 3.0.0~alpha.8-1u3
(https://github.com/LibreTime/libretime-debian-packaging/releases/tag/debian%2F3.0.0_alpha.8-1ubuntu3)

On Mint 18,(Ubuntu 16)

I have downloaded the .deb and copied it to a folder I made called LT

I then try:
sudo apt install icecast2 ./libretime_3.0.0~alpha.8-1ubuntu3_amd64.deb
[sudo] password for spot:
Reading package lists… Done
E: Unsupported file ./libretime_3.0.0~alpha.8-1ubuntu3_amd64.deb given on commandline

Also
sudo apt install icecast2 ./LT/libretime_3.0.0~alpha.8-1ubuntu3_amd64.deb
Reading package lists… Done
E: Unsupported file ./LT/libretime_3.0.0~alpha.8-1ubuntu3_amd64.deb given on commandline

And

sudo apt install icecast2 Libretime_3.0.0~alpha.8-1ubuntu3_amd64.deb
Reading package lists… Done
Building dependency tree
Reading state information… Done
E: Unable to locate package Libretime_3.0.0~alpha.8-1ubuntu3_amd64.deb
E: Couldn’t find any package by glob ‘Libretime_3.0.0~alpha.8-1ubuntu3_amd64.deb’
E: Couldn’t find any package by regex ‘Libretime_3.0.0~alpha.8-1ubuntu3_amd64.deb’

2

Try use apt-get instead of apt or try use the PPA - https://launchpad.net/~libretime/+archive/ubuntu/libretime/