I have looked on youtube and this forum for information about dithering, and I haven't found anything that helps me.   It tells me what it is, but doesn't really explain how to do it.
I recorded all my songs in 24 bit.   After I'm done mixing, I export it as 24-bit, then import it to master it.   But I heard that I'm supposed to export it again as 16-bit.   I don't know how to do that.
 
If anyone could point me in the direction of how to understand this, I would be very appreciative.
 
Thanks,
Greg

You may simply select 16/44. in the export window, The rest is automatic.
Also note the powr 12&3 options. If you do nothing the default setting should be fine.
 
Export>select type of file and title, bitrate and if you want efx on or off....oh and if you'e using ARC. Don't export though it.

The general rule is to apply dither when you reduce the bit depth, which is generally the last step in processing. You can certainly master at 24 bit and then only apply dither at the final stage of conversion to CD quality (16 bit). Many professional mastering houses prefer to receive the output in the bit depth that it was originally recorded to. 

Thanks, starise and slartabartfast!  I appreciate your help.
 
Greg

This is an article from 2013, and the attachments with the audio examples seem to have unattached, but you might find it helpful.

Thanks, Craig!
 
Greg