I have been trying to create a visual , I also went through the tutorial videos and was able get started with the visuals but there are a lot of pre-requisites knowledge required to built a complete visual. can anyone reffer any link to learn about these pre-requisites like ( the Power BI functions and api's / D3js).
Currently, based on my research, you could start with Sample Bar Chart Repo. Try to make some changes and debug the project in Web Console. Feel free to raise questions here.