Here's the link to an online version of Sunan Abi Dawud: https://sunnah.com/abudawud
We should learn Ahadith because, the experts of this science say that the purpose of studying the science of Hadith is to attain the blessings that are reported in the Ahadith about those who engage in teaching and studying of Hadith.
The second purpose for studying the science of Hadith is that this religion is dependent on Hadith, because the Qur’an is concise and it is in need of explanation to make things clear, and that can only be accomplished by the Ahadith. For example, the Qur’an mentions the Salah (Prayer) and Zakah (Obligatory Charity), but it doesn’t mention the specific numbers of Salah and for Zakah. Such details are known from the Ahadith.