r/MachineLearning - [D] Tensorflow graphs, custom estimators.. what?

Just for some background, I have been using tensorflow but with the Keras API. But now my job role requires a project where a custom Estimator is needed to be made for a weight based multi class multi label classifier using the dataset API of tensorflow. These are all new topics and although tensorflow docs have information about each topic, I am extremely confused as to what flow to make and which modules to use. It would be of great help if someone could point me towards some material to understand these topics and give some advice towards making a classifier of above mentioned kind. Also a side question: which loss error should I use and how do I incorporate the weights? EDIT: The weights associated with each label (from the multi label dataset) is actually the conversion rate from search page, i.e. (#of orders / # of appearances on the search page)