Thanks, finally figured it out:

Double click Macintosh HD.

You will get your Finder.

Navigate to Blockland and right-click it.

You will see this list.

Choose get info.

Then you get this.

Go down to "sharing and permissions".

We notice that they are all "read only" except for (Me).

Click this next to "everyone".

Now, you want to set it to "read and write".