how do you turn on monitor

There is no external buttons on the display.

Simply plug it into a power outlet, then plug it into your computer (with the display open) and it will turn on by itself.

The LG manual and support page web address is in the article...

"You can download the LG UltraFine 5K Display owner's manual

and LG Screen Manager software on the • LG support page..."

That hidden LG Support link appears thus:

http://www.lg.com/us/support-product/lg-27MD5K

LG Help Library:

http://www.lg.com/us/support/product-help?search=27MD5KA-B

Good luck & happy trails! 🙂

After looking through the LG site and also the Apple Store link, hoping

to find a detailed view that shows controls or buttons, I'm disappointed.

There does not appear to be a diagram or image of this display showing

controls external to the unit. The download manual may show this detail.

IF there are any Button-like features on the back, nearer the AC power port, look.

On the presentation of their 'absence of detailed views' online, I can only hope

the LG site offers a downloadable manual; to show exacting features such as a

power-on button. On the face of it, I would be not wanting this unit.

Good luck & happy trails! 🙂

Yes, that was covered in the link(s) from the makers site.

And was primary the reason for posting those, nearly a

month ago. Not having heard back, this thread's author

must have figured something out by now.

However there wasn't a clear diagram of the product; yet

an owner of the product would have documentation in the

box that likely shows most those details & how to set it up.

I've a Samsung display that has only a power key. If I didn't

know to download the Control Software, no Brightness or

Contrast setting could be adjusted. That can be found on

their site; (a download) if one knows where to look.

When someone gets a second-hand display without a manual

sometimes missing detail can be minor inconvenience to next

user of the product.

Thank you for your help.

Good luck & happy trails! 🙂