Mod ID:
On a mod's main page ie "description tab" right click then click "copy page url" then paste it into any area you can paste text ie the steam comments window or windows notepad etc.
Works for all steam workshop mods for any game.

The mod id is clearly shown in the url. Here it is for the valley.
?id=1751879225

http://prntscr.com/plfndu

Map Name:
For the name of the map to use go into your ark install directory then "/shootergame/content/mods/mod_id" and look for mod.info file, open it in a text editor and there will be two name entries, they are often the same but if not the correct mape name is usually the second one.

http://prntscr.com/plfomq

Thanks for mod ID. BTW it may be in the URL, but it is NOT clear to potential players, hence my post. I'm sure there are others that are thankful for the mod ID to be clearly noted. Best to listen to your "customers" feedback if you want players to use mod. Thanks again. -Odin

Max isnt the map designer. He is a "customer" helping another "customer" out. And it is common knowledge when using mods that the ID is listed in the URL as its not always listed in the description.

The map name has to be TheValley (no space) as well.

Sorry mate, but it is not true that it's "common knowledge". I've played many thousands of hours and I was not aware of this. The experienced owner of the server that I'm playing on was also not aware of this. If mod owners want people to use their mod they need to post the mod ID number clearly just as other mod creators do. Enough said.

I agree Odin. There are a lot of Steam users who do not have the address bar visible from the Steam/Settings/Interface tab... "Display Steam URL address bar when available". It's usually off by default. Any modder can show consideration for this situation by just having it in the description, and for maps the used map name for loading purposes. This is very easy to do and never has to be done again once it's in the description