I need help looking for a guide on military and units and stuff can some one direct me to a guide on this tuff

Only those in your alliance. Other than that no

you can give them warning but you can't defend it. But there is a way if your ally won't be able to save it from getting razed. Then you can save it. Take that outpost kill enemy units. Give it to your ally later.

wait which ones true

If the person is in your alliance then you can defend it (are they marked green). When you become friendly with another alliance, you tend to call them your ally and mark them blue.

So it depends what you mean by ally. If they are marked green, then yes you can defend their op. If they are marked blue, no you can't, however you can tell them they're being attacked.

i meant in the alliance
thx

In alliance you can defend everything colony, relic,outpost, to your nuke quiz , answer is simple can you see nuke on other player silo. Yes you can. So they will also see it.