Polar codes have received significant attention in the last ten years, both in academia in industry, with this interest culminating in their inclusion in the 5G standard. This tutorial aims to give the audience a solid understanding of the principle behind polar coding, an in-depth knowledge on various decoding algorithms, and some basic guidelines related to implementation aspects. More specifically, in Part I we discuss the basic principle behind polar coding and the successive cancellation decoding algorithm. In Part II, we describe several decoding algorithms with improved error-correcting performance, while in Part III we focus on decoding algorithms with reduced decoding latency. In Part IV, we go over several non-standard constructions of polar codes that aim to either reduce the decoding latency or improve the error-correcting performance. Finally, in Part V we give some basic dos and don’ts when designing algorithms that make their hardware implementation easier.