Dont know what the tuning sites say but if you have the ability to tune 2 strings so they sound the same then there is a simple method if you havnt got an electronic tuner to hand.

Tune the bottom string, (for the purpose of this method thats the one furthest away from you as you hold the guitar in the usual position for playing but the one that plays the highest note) so that it plays E. The recorder will give you a suitable E.

Then put your finger on the 5th fret of the next string up and tune it so that it plays the same note E. Play the two strings one after the other, adjusting the 2nd string with the tuning peg until you get them to play the same note E (remember to keep holding the 2nd string down on the 5th fret).

Do the same with the 2nd and 3rd strings but this time holding down the 4th fret (the note is B this time).

Then the same with the 3rd and 4th strings but this time back to the 5th fret (G this time).

Carry on with the 4th and 5th strings, again on the 5th fret (note D), and finaly the 5th and 6th string still on the 5th fret again (note A).

As a final check play the 6th string (the lowest sounding) against the 1st string (the highest sounding). They should both play note E but 2 octaves apart (a low E and a high E). This should get you somewhere close and you will get better at it the more you do it. Good luck.