Importing a survey
From LimeSurvey Manual
Importing a survey structure is done by clicking the Create new survey button and selecting the Import tab:

To find out more information on how to do it via LimeSurvey, read the following wiki section: Surveys - introduction#Import a survey.
If you do not want to use LimeSurvey to import a survey structure, access the following link on Alternatives to the LimeSurvey import function.