Hello stigbarrett.

Thank you for your purchase.

If you can't find it in the .po file, or if the changes don't take effect, you can open wp-content/plugins/wpdatatables/source/class.wpdatatable.php around line 3257 find this line of code:

                array(
                    'text' => __('New entry', 'wpdatatables'),
                    'className' => 'new_table_entry DTTT_button DTTT_button_new'
                ),
                array(
                    'text' => __('Edit', 'wpdatatables'),
                    'className' => 'edit_table DTTT_button DTTT_button_edit',
                    'enabled' => false
                ),
                array(
                    'text' => __('Delete', 'wpdatatables'),
                    'className' => 'delete_table_entry DTTT_button DTTT_button_delete',
                    'enabled' => false

And after 'text' => you can change 'New entry' to whatever you want. Same goes for 'Edit' and 'Delete' of course.

For "Nothing Selected", you can open wp-content/plugins/wpdatatables/source/class.wdttools.php and around line 361 find this line of code:

'nothingSelected'           => __('Nothing selected', 'wpdatatables'),

Just change 'Nothing selected' to whatever you want it to be and that's it.

I hope this helps.

Best regards.