Grateful for some assistance

I am a guitar rookie (as in GTrick's lesson 3) and recently bought the ST-8.

When I use the tuner and attempt the tune the strings the tuner gives me sting letters that don't correspond to EADGBE. For example, low E (6th string) is shown as D according to the tuner - that said, Im able to tune it to the green bar (or close to). The tuner is clipped to the headstock

Help please / what am I doing wrong?

Thanks

Neil