How to create username with firstname and lastname using feeds and tamper? On Feeds tamper module page (amazing module btw), it says that the module permits to [...]

Examples:
[...]



  Combine separate 'firstname' and 'lastname' fields into one 'name'
  field.



But I don't find any documentation on how to do this. Any help?
Depending on your source data, you want to use the "Rewrite" plugin of Tamper to combine the fields. More described in: https://drupal.org/node/1973776