Where are the Cubelets?

[Moos_]

5 minutes ago, I completed the Summer Quest and got rewarded for it, one of the rewards was a Cubelet.
Where can I open the Cubelet? I'm currently playing on Bedrock and I just can't find the place to redeem it.
Could someone please help me?

 

[OyTekla]

5 minutes ago, I completed the Summer Quest and got rewarded for it, one of the rewards was a Cubelet.
Where can I open the Cubelet? I'm currently playing on Bedrock and I just can't find the place to redeem it.
Could someone please help me?

I’m pretty sure that cubelets are only for java edition