Hi, eating meat is probably the best way to get those nutrients but it is not the only way. While it is still hard, I don't deny that, it is possible to get all the required nutrients from a vegan diet.
The diet should be based around plant foods and crops. Many fruits and vegetables and an attempt should be made to eat as wide a variety of these as possible to meet nutritional needs. As a general rule darker vegetables are a great source of nutrients such as dark green leafy vegetables (kale, spring greens etc.). Over processed and unnatural foods should be avoided if possible, because many of the worse foods from a regular meat eating diet can still be eaten on a vegan diet. Oils such as hydrogenated vegetable oils containing trans fats should be avoided. You may also find that hydrogenated fats that contain trans fats and tend to be hard at room temperature, are ingredients in some vegan burgers and sausages and similar products so labels should be checked to look at this and not just to see if the products are suitable for vegans.
Because animal foods are good sources of nutrients such as protein, iron, zinc, and vitamins such as b12, and dairy products are good sources of calcium, vegans do tend to use food supplements. This is not essential because these things can be found in vegan suitable foods. Zinc and iron can be found in many whole grains, nuts, seeds and legumes. Protein is found in decent amount in most plant foods and legumes. Calcium is present in good quantities in things like spring greens, kale, mustard greens chinese cabbage, and soya milk. Soya milk can also contain vitamins d and b12. However, vitamin b12 is only available in fortified soya milk and it is the most common deficiency in vegans. Therefore this is the most popular supplement for vegans.
Hope this helps.
Concho