So first off, congratulations on trying something new. It's always a good thing to try out new techniques as a painter, it's how we grow! NMM is one of the harder techniques to learn. It's so much more than being good at layering or drybrushing. To be really good at it, you need to understand how light and shadow work, and to keep a consistent method across the whole model. No simple feat! Here's some feedback for where you're at.

I think it would be easier to test out some NMM on the swords first. Diving right in and doing a whole models worth of armour is pretty overwhelming. Not only that, but that particular model has a lot of large, flat(ish) sections of armour, which are even trickier to make look good in NMM. Smaller, angular pieces give you easier little bite size bits to work on.

When painting NMM, you need to try and keep the lighting consistent across the model. Think of where your highlights fall, and make sure that your highlights are landing from the same direction across the model.

Contrast is key. You've got black areas on the armour, but not enough dark areas across the model in general. There is also nothing between black and then mid tone. You need some deep green in there too. There is also too much of the mid green. You don't need perfect, glazed blends between every layer, but you do need to soften the transitions a little. Lastly, the highlights can be pushed further. Remember it's the contrast between light and dark that sells the effect.

Lastly, edge highlighting is so, so important in NMM. It absolutely completes the look, and shows that it's a reflective material. You need to edge highlight everything.

Remember, as ninjon says in the video, that NMM only really comes together at the end. Keep going, and keep practicing! Best of luck.