All your cards can be found in the BUILD MENU.
Cards are sorted by CATEGORIES, SUB- CATEGORY and in TABS.

Tap on the CATEGORY to the left of the screen to see the SUB-CATEGORY selector.
Tap on a SUB-CATEGORY to see the list of cards.
Tap on TABS to filter different card collections.

When on a list of cards, you can tap on the RETURN (Red Arrow) button, to the right of the TABS, to go back to the SUB-CATEGORY selector.
You can also tap on the CATEGORY on the left side, anytime. This will display the SUB-CATEGORY selector. 
To place the items, DRAG THE CARD  into the park.
CONFIRM the position.