I would suggest that you start with the following:
1. Get access to Anaplan, so you can start building models in your own sandbox environment. Nothing beats actual hands on experience.
2. Go through at least L1 and perhaps L2 of the model building courses offered in https://learning.anaplan.com/totara/dashboard/ These 2 courses will teach you basic navigation within Anaplan, while you slowly get familiar with the jargons, and best practices in Anaplan..
4. Subscribe to the forum that you just posted this question, and check it out constantly. It's very likely that a problem you'll face in Anaplan has been faced by your counterparts from all over the world. There's healthy ongoing discussion, and later once you feel more confident you can also contribute to the community.