What books do I’ve to buy?

You’ll have to buy the books below & you can buy them from Amazon.com:

1. 1. PMBOK Guide 6^th edition: https://tinyurl.com/2p98s8mu
   2. PMBOK Guide 7^th edition: https://tinyurl.com/bdduuusj
   3. Agile Practice Guide: https://tinyurl.com/mt4d9wck