Develop creativity with composition project. Sure children can learn already written songs, but you'll find them much more engaged if they are writing the songs themselves.
With grade 2 students we also learn Melodic Notation, so *sometimes* after we finish a composition, I ask the children to copy their notes onto the Treble Staff to practice conventional notation systems.
In an IB school setting, inquiry based learning is very important - where the children are the center of the learning.
Suggest to children to tick off each step as they complete it to develop self management skills. You can guide them through this while you circulate through the class. When children complete all the steps, you can perform it to the class so they can hear what it actually sounds like.
I also included reflection questions at the end for classroom discussion. It's important for children to reflect on what strategies they are using and what else can they try next time.