I use EaseUS Backup as well, very good program. What you will need is:
1) drive to backup to. I suggest an external USB drive which you can backup everything to, then unplug and put somewhere safe. You can get a 3TB external drive now for $125.00 or so from almost anywhere (or cheaper if you shop carefully).
2) Download and install the EaseUS backup software.
For the first backup, I would do two backups.
First, do a full system backup of your installation. This way, if the system goes to complete hell, you can restore it and have everything you need back and functional.
Second, do a backup of the specific files that you want backed up. The reason why is simple enough: after you do the original backup, subsequent backups can either be a differential backup which takes far less time. Differential or incremental backups basically means that your only backing up files that are 'different' from what it already has backed up - so - only the changed files, not the full set. Much quicker.
Last thing to do is this: PUT THE INSTALLATION FILES FOR EASEUS ON THE BACKUP DRIVE. Just in case something happens to EaseUS - they go out of business, their backup methods change, website gets hacked, or you just don't have access to the internet, you can always reinstall a basic system OS, install the backup software, and restore your files.