Errors in the guide for setting up user quotas on Ubuntu 14.04?

Following this guide: https://www.digitalocean.com/community/tutorials/how-to-enable-user-and-group-quotas

Everything seems to work until this step:

quotacheck -cum /

The error text I received is:

quotacheck: Mountpoint (or device) / not found or has no quota enabled.
quotacheck: Cannot find filesystem to check or filesystem not mounted with quota option.

I tried edquota some_user, just to see if I could get any further. The error for that was:

No filesystems with quota detected.

I’m pretty clueless with all of this, so I’d appreciate any help.

Thanks!