I just took a look at the app and I indeed can't find the sources you need there. I don't know if they are not there, of if they are hidden somewhere I didn't think of looking, but either way, I can imagine that it is hard for somebody new to the network to find them.
If you visit the web site at cooking.stackexchange.com, you will see a "help" menu in the top bar (look at the place I marked yellow):
(you will probably not have the "mod" and "review" menus, you need to be moderator for the first and have enough reputation for the second).
The menu has three options:
"Tour" will mostly teach you how a Question-and-answer site works (as opposed to a discussion forum). It will give you information on the only-one-question-with-many-answers format, voting and such. It is very short and basic.
"Help center" is more specialized. It has short articles on what is on-topic, what closing reasons there are, what style of answer tends to be upvoted by the community, and similar. It is close to what other sites would put in a FAQ or knowledge base.
"Meta" is a second site dedicated to discussing stuff not about cooking, but about the cooking site itself. It uses the same question-and-answer format as the main site, but the scope (the rules about what is on-topic) is different.
Meta is used in different ways. People who don't understand something specific can ask here for help. If you find a bug, you can also report it here. It is also used for discussions within the community, for example decisions what to do with "grey zone" questions which are not forbidden in the on-topic list, but tend to get the requisite five community close votes to get closed.
This is a bit similar to a country's legislature. There is a compilation of all laws (similar to our help center articles), but if you want to know how each detail is handled, you need to know what court decisions have there been in the past (our Meta threads are an analogue to them).
But don't worry. We don't expect new users to have read the whole of Meta; most existing users have not. Reading the Help center is encouraged, but also not completely necessary.
One thing you should understand is that what we are doing is not about punishment. Closing questions, deleting answers and downvoting has the goal to keep the site content the way we want it to be, not to punish users who have created "wrong" content. I know that it feels very unpleasant when it happens to you personally, but if you manage to get a degree of detachment, you will notice that it is not that bad when it happens. If you use the site in a way it is not intended to (for example, ask an off-topic question, or leave an answer which does not address the question), all that happens is that we stop this use and tell you what you did wrong. There are no punishments or reprecussions beyond that, there are no black marks on your record (OK, downvoting reduces your reputation a bit - but you only lose 2 rep per downvote, and a single upvote gains you 10 reputation). There is nothing personal in these measures; I may even delete your not-on-topic answer on one question, and a minute later upvote your answer to another one. Everybody makes mistakes (moderators and high-reputation users included); when we do it, the community reverts your action (deletions by moderators are often based on flags cast by members), and everybody moves on.
Asking about the way we are doing things already makes you different from the crowd who bitches that the rules are stupid because they didn't expect them to apply to their question. Thank you for doing it, and for your willingness to learn about our ways. I hope that the existing material will help you, but if you find something you still don't understand, you can ask here on Meta, or more informal in chat. Note that chat has no on-topic rules, and if you have a question of the type not allowed on the main page, you can get advice in chat on it. The downside is that you will only be speaking to the few chat regulars, not getting all the eyeballs present on the main site.
