There are multiple ways to install YunoHost. The process may slightly differs whether it takes place at home or if you want to do it on a remote server, and regarding the hardware used: See the requirements
This page lists a few installation guides.
Give it a try
Install @ home
On a virtual machine/container
On a remote server
If you have already installed Debian 8 (Jessie) on a server, you'll be able to install YunoHost with a simple script.