Method 1

Step one: Choose a panel and add it to the closet.

Step two:

First, choose Select Part, then Single-click the panel, Choose duplicate to add more panels.

Or choose Panel array.

Step Three:

Finished adding.

Method two:

Step one:

Choose a panel and add it to the closet.

Step two:

Use Panel Array to add more panels.

Step Three:

Panel Added.

Click on the panel, and you can choose to Delete in the Toolbar.