If you have good programming skills then it will be much easier to learn Big Data and Hadoop programming.
Since you have prior programming experience than you can learn Big Data and Hadoop much easily.
Start with Basics:
First of all you have to learn the Basics of Big Data and Data Analytics. After learning these you will gain knowledge of Big Data and its applications. Understand working of Big Data and its Big Data Platforms.
Next step is to download and install Hadoop for learning on your computer. You should learn try with many examples of using the Hadoop for managing the data.
Learn Map Reduce:
Next thing is to learn the Map Reduce, which is used in Hadoop for various processing and analytics work. This will give you great idea of using the Hadoop for Big Data.
Learn HDFS and YARN:
Both these are important and you should devote more time in learning these.
Learn Hive and Impala:
Learn how to use Hive and Impala in Big Data development.
Other things you should learn are:
Check topics at Big Data and Hadoop Training.