On a Debian distribution (Mint, Ubuntu), apt-get install can be used to install snapd. On a Red Hat distribution (CentOS, Fedora, Red Hat), dnf install or yum install can be used.

dnf install snapd

Start and enable snapd.

systemctl enable snapd
systemctl start snapd

Use snap to install core.

snap install core

The snap list command should now include core.

~]# snap list
Name  Version    Rev    Tracking       Publisher   Notes
core  16-2.59.5  15511  latest/stable  canonical✓  core