How to Attach/Detach the Joy-Con 2 Controllers from Nintendo Switch 2
How to attach the Joy-Con 2 controllers to and detach them from the Nintendo Switch 2 console.
Complete these steps
Are you attaching or detaching the Joy-Con 2 controllers from the console?
Orientate the console so that it's upright and facing you.
Bring the right Joy-Con 2 (the controller with the + Button) to the right side of the console.
Align the bottom of the controller with the console, then bring the top close to the console. You will hear a click when it is securely attached.
Keep the area between the Joy-Con 2 and the console clear, being careful not to pinch your fingers.

Joy-Con 2 (R) controller being connected to the Nintendo Switch 2 console
Repeat steps 2 and 3 with the left Joy-Con 2 (the controller with the - Button).
The attached Joy-Con 2 controllers are ready to be used and will also be paired to the console. They can now be detached to use wirelessly.
Important: After detaching the Joy-Con 2 controllers from the console, be sure to attach the Joy-Con 2 straps before starting a game or software.
Press the release button on the back of the Joy-Con 2.

Release button on back of Joy-Con 2 highlighted while controller is attached to the Nintendo Switch 2 console
While holding the release button down, pull the controller away from the console to detach it.

User pressing release button on back of Joy-Con 2 and detaching the controller from Nintendo Switch 2 console
Joy-Con 2 pairing information is not deleted when the controllers are detached. You can now use them as wireless controllers.
Additional information
Up to 10 controllers can be paired to one Nintendo Switch 2 console.