The basket will empty if you log out of Evergreen.
To add a record to the basket, first find the record by conducting a search in the Staff Catalog.
Then, check the checkbox that appears between the result number and the cover image of the desired bibliographic record in the results. The record is added to your basket, and the number next to the Basket Actions button in the search form increases.

To add all records on the page to the basket, check the checkbox between the search form and the search results. This will select all results on the page.
To add a record from an additional page, navigate to the page where the record appears and check the checkbox of the desired record.
To add all search results, click the Basket Actions button to expand the options, and click Add All Search Results.
If your search returned many results, this action may take a long time.

To add records directly to a bucket and skip the basket, see the Buckets documentation.