I can access lesson 1 of basics 2 but the other lessons are locked. How can I access the other lessons in basic 2 or do I just keep on practising lesson 1 until something opens up? Thanks for your help.
You have to 'pass' Lesson 1 before you can do Lesson 2. That is, get all the way to the end (20 questions, I think) without getting an answer wrong after losing all three hearts. Every time you pass a lesson, the next lesson in that Skill group opens up. When you've done all the lessons in a Skill, the next Skill opens up (sometimes more than one Skill, depending on how the tree is structured).
The system is designed to make sure you do everything in order, and don't skip ahead to avoid the hard parts!