When I try to add an attribute to one entity it works but when I try to add a second entity with an edited attribute it doesn't work. The wiki does not state how to add multiple entity attributes.
help.txt

Help would be much appreciated.

Hi there,
No worries, your problem is just a bit of malformed json - here is what you need:

{
    "values": {
        "adventurez:amethyst_golem": {
            "minecraft:generic.max_health": 240.0
        },
        "adventurez:stone_golem": {
            "minecraft:generic.max_health": 2400.0
        }
    }
}

The wiki assumes a prerequisite level in json, but you're right it could be clearer on some things, I'll make some amendments.
Hope that helps, thanks.