Where's the Manual?

I have several hours today with a few issues while working with Custom Fields.  I discovered that Wrike does not have any formal documentation but instead relies on 1000's of postings from others who may or may not share your issue.  Where does one get specifications?  How long is the field length in a "text" custom field?  How many expressions can be included in a custom field formula?  Brackets "[ ]" are used to surround the formula variables, but additional arithmetic expressions use parenthesis but where is that listed?

Wrike is a fantastic product so why when I call or chat I'm directed to YouTube videos or a self-help FAQ/Community board?