How to transfer photos from Computer to cell phone?

Hiya....

I need help transferring photos from my computer to my :

Motorolla G2

I found these instructions:

https://support.motorola.com/us/en/solution/MS1486...

But its not working for me.

In the instructions it says to "Unlock your phone"....I dont know what that means.

"If you don't unlock the phone and change the USB connection to allow file transfers, you won't see any files on your phone"

On the phone I am able to get to the screen:

USB for photo transfer

and I did change the selection on USE USB FOR

to Transfer Photos or Transfer Photos

and then I try and copy and paste them to the phone....

but they dont show up on the phone or like it said....above I dont see any files

on my phone nor do they show up on my computer when I access the phones folders.

What am I doing wrong.

Thanks for you help