Each mod is created for a specific version of a game. Obviously the current one when the mod was released, but there's some probability it will not so much be the current one a few months later.
So to be sure a mod is working, we have to check what is the current game version.
The matter is : No Man's Sky is updated quite often. In fact, some times very often.
Ad there's the public branch and the experimental branch and both could have different versions. So some mods could work with the public branch and not at all with the experimental branch!
And more annoyous : There's no game version displayed anywhere in the game!
Steam Build ID
To palliate the version issue, it was eventualy noticed that Steam was giving unique IDs to each and every game release, either for Public and Experimental branches.
So since quite some times now, modders are refering to game version by their Build ID.
To know what's the Build ID of your game, you just need to right-click on it in Steam and choose Properties.
Them select the Local Files tab and look at the bottom of the panel and you will find the Build ID.
How to find your build ID
Another way to get this information is to check the No Man's Sky Steam DB depots page.
SteamDB not only displays current Public Build ID, but also the Experimental one, and even the internal (reserved for developpers).
On the capture below, we can see that all the versions are in synch, but that's not always the case.
As stated above, NMS has two accessible development branches : a public and an experimental one
They are separated games depots and each one can be updated independantly.
To know what branch you're in, it's simple : if you bought the game and are playing since then, you are playing using the Public branch.
To switch to the experimental branch, you need to right-click on NMS in Steam, choose the betas tab, select Experimental in the list of betas available and enter the password : 3xperimental.
If you do so, Steam will load the files that are different between the Public and Experimental branches and will always start in the experimental from now on. Until you go back into the betas tab and choose : no beta. If so, it will switch back to Public.