I'd start with a teaspoon (like this recipe: https://www.nutriliving.com/recipes/maca-energy-machine) and then work your way up in 1/4 tsp increments. Maca is an adaptogen so if you take it continuously your body will become used to it and you may not receive any benefit. You can work your way up to a Tbsp, but I wouldn't go beyond that. Here's a recipe:
Try either rotating superfoods and taking some time off from maca every now and then so it remains effective.