To access your block storage, it has to be assigned to a cloud server hosted in the same data centre. Please note that a block storage can only be assigned to a single cloud server. After assigning it, you will have to adjust the disk configuration in the operating system of your server.
Select the desired block storage.
Click on the pencil icon next to Assigned to.
Select the server to which you want to assign the block storage.
Click Save Changes.
The block storage will now be assigned to the cloud server.