There is a huge amount of information out in the world about health and it can be very confusing, especially as so much of it is conflicting too. To start with pick the easy things. Leave the conflicting advice for a day when you have sorted out the simple steps.
You know you want to do something but you don't want to get it wrong. Sound familiar? Just take one step - that first one is often the hardest. It might be a decision to avoid sugary drinks, and/or increase your water consumption. Or to eat real food by making your meals from real ingredients and not from a packet. Or to optimize your vitamin D levels, now you know how important it is (if you don't know yet there is more information on my website about this). Whatever you think you can manage easily do one thing to make it happen, right now. So go to the local Veg Shop, order your supplements, go in the kitchen and drink a glass of water or even just get up and move for a couple of minutes.
Every minute of every day you are only one decision away from improving your health. So just do it!