Hi,
What do you mean by ' I was trying to do that but the site didn't let me do it...' ?
At least, if the JText is activated for Seblod, you should see some labels on your website displayed like 'COM_CCK_...'.
If that's not the case, this means it's not enabled.
I use to add my custom translations in the override language file located in 'language/overrides/tag-TAG.override.ini'.
Olivier