Who - An unnamed psalmist speaks to the people gathered for worship.
What - A psalm of thanksgiving and a call to obey the LORD. This psalm is a psalm for corporate worship, though it could be for any size group or even an individual.
When - Unknown
Where - Unknown
Why - The psalmist is calling the people to come and worship the LORD, to sing and delight in the LORD because he is a great God and King. And also because those gathered in worship are His people. The psalmist warns the people not to be unfaithful like their forefathers at Meribah and Massah, primarily not to go astray in their hearts.
