- Install Virtualbox or VMware
- Get a Debian/Ubuntu Server Iso and install it
- You don't need more then 1GB RAM, 1-2 Cores and 20 GB Diskspace
- Configure the network adapter as a briged network
- get putty or any ssh client you want
- snapshot the server when you're ready, so you won't have to install it over and over after making mistakes
- start with small projects (learn to navigate through folders, learn to use vi/vim, learn how to install packages, where to find all config files,...)
- get into Unix permissions (users and groups, read, write, execute)
And the best thing, all of this is free. And even the weakest computer is going to run such a VM. Don't start with a vps hosting. It's not worth just for learning purposes.
If you need help consider to use google for answering questions. (I don't want to be rude, but most basic questions have been already answered there.)
And if you feel safe and good to go, learn how to secure an VM (fail2ban, firewalls, ...)
Everything else is learning by doing.
On any questions just tag me. ?