I think that perhaps part of this is down to the interface not making things as obvious as they could be meaning that you really do need to read the documentation in order to understand the full capabilities of Darktable.
Echere m na ikekwe akụkụ nke a dị n'okpuru interface n'enweghị ihe ọ bụla doro anya dịka ha nwere ike ịpụta na ịchọrọ n'ezie ịgụ akwụkwọ ahụ iji ghọta ike zuru ezu nke Ọchịchịrị.