To help solve the cipher challenges, check out this GitHub repository of interactive Python programs.
If you know absolutely nothing about cryptology, but you are interested in learning more, consider one or more of the following options:
Read sections 2 & 3 of this paper, which provides a comprehensive overview of the field
Watch the code-breaking tutorials or read through the guide section on the Great Cipher Challenge 2020 website
Pan through the slideshows on this website