The process for adding this block to a page is very straight forward. Choose 'Add Block' in any editable area and then choose the Stock Quote block.

You can look up the stock's symbol on http://finance.yahoo.com/ if you do not know it off hand and enter it into the field. Next choose what information you want to display and click add. If you prefer to have the fields display stacked, click on the block and choose Custom Template and then choose the 'Stacked' option.

If neither of these formats look as desired on your site, copy the default file from /packages/triplei_stock_quotes/blocks/stock_quote/view.php to /blocks/stock_quote/view.php and modify it to your needs there. There is an extra example and some documentation available in the header of the file.