Can you click a mouse? Know what a hyperlink does and looks like? Attach a document to an email message? That is about as advanced as you have to be to start using Moodle in a way that most users begin to use it – as a ‘digital cupboard’, a storage space for your files and folders where you and/or your students can view and download them 24/7.
But don't be boring and use it JUST for that. Even some of the basic interactive activities like Forum or Choice for example, do not require a great deal of skills – just a little bit of imagination.
You can certainly get a lot more out of Moodle as your proficiency grows but don't burden yourself too much about it. Do you have to know all about the fine inner workings of a particular car before you drive it?