Every now and then we have such questions from newcomers and this is a perfectly natural question for them.
I thought that if we have a central guide (either here on meta or on the main site) here, and maintain it, both sides will be happy, as we can close these question as duplicates / hopefully get less and the newcomers get their answers. In my opinion the combined answers to such a question should cover questions of the following style(s):
- I just want to learn classical Cryptography
- I just want to begin Cryptography
- I want to learn side-channel Cryptography