What is the difference between tuning your guitar and intonating it?

Intonation is moving your bridge saddles so that the 12th fret harmonic matches you open string note on a tuner. More or so there's more to it but you can search for further details.

Tuning well we all know that it's about tuning your open strings with a reference (tuner, pitch fork etc). Most will tune the A string and go by ear from there.

Hope this helps

Confessed Pickaholic!