Hi Philip,
I'm glad the above has been helpful.
In regards to your query, the following links are the only guides on the topic we have at the moment.
https://www.clearbooks.co.uk/support/guides/codes/adding-new-account-codes/
https://www.clearbooks.co.uk/support/guides/codes/can-i-edit-an-account-code/
As Kevin has kindly explained, the basic principle of how the account codes/types work is relatively simple, once you get your head around it. Clear Books can actually help you understand this better, as it comprehensively list these into categories, as per screenshot below.
So, if you head to Settings > Codes > All, you will be able to see all the account codes listed by name, which statement (Profit and Loss or Balance Sheet) they are included in, which account type they fall under etc. This should hopefully provide some structure and help you make a clearer distinction between the categories.