Every item has a Content Type e.g. article, hotel, car
Normally every item will use the (item layout) of the template defined at Content Type configuration.
To display your fields in frontend item view (*like joomla's article view)
-- Go to your item and check which template it uses (it will be either Content type predefined template, e.g 'blog')
-- Goto template management and edit the item layout of the template you found above e.g. 'blog'
-- Add your fields in various template positions
NOTE some templates (e.g.) besides template positions also have parameters with which you can enable / disable showing CORE fields , e.g. created by user. These can be edited in (recommended) Content Type Configuration and (not recommended) in each's item form