How do I find missing parts for the Outdoor Bookshelf?

In the Restore the… Outdoor Bookshelf you have to first find some missing items (9 board pins and 5 shingles tiles) on your farm.

To do this, just plant and harvest crops as usual.

When the parts start showing up, click on them.

After you find all missing items, install them by clicking on each part in the Building Renovation Panel.