Hi Marcelo,
You can use the Start/End Loop Through Grid actions to look for checked rows in a grid. These actions allow you to loop through a grid for records that match specified criteria, performing actions on them one by one. In this case, you'd want to configure it to loop through only checked rows.
You can then use the Insert Records Into Table action, which you can configure to insert fields based on Value From Row. Value From Row means the currently selected record in a loop, so it'll take the current record in your Loop Through Grid action, grab the specified fields for that record and insert them into your table. If you place this between your Start and End Loop Through Grid actions, it'll be performed for each record found by your loop.
Hope this helps.
- Justin