meal prep for newbies

So I am starting to get interested in doing meal preps but I need some help on this. If anyone has any links or apps that would be really helpful then please let me know.
I am not sure about what will spoil, what shouldn't be prepped ahead of time and mixed together, etc.
I am a vegetarian so my sources of protein will probably be tofu or soy protein pattys.
I would get sick of eating the same meal 2 days in a row so how do you keep variety without wasting food?

Thanks in advance