Once you obtain a new subscriber it is a good idea to welcome the subscriber with a newsletter/e-mail designed for this purpose. You can use this aproach if you are, for example, giving an e-book to new subscribers etc.
Stages is the way to go
In order to start, you have to create a stage in part of a course. Courses are e-mails that are sent in intervals that depends on the subscriber(s) sign up date. Open the tab Lists & receivers and click Courses and click at the list in the overview to the left.
Click Add new stage and enter a new subject, for example, Welcome to our newsletter. Chose a template and confirm by clicking Add new stage. The click Edit content - you are now being directed to the same editor you use when you create newsletters.
Type the content into the editor - It can be to your advantage to link to the latest newsletter if it contains information that is relevant to new subscribers.
Quit the editor once you are satisfied. Your welcome e-mail is now ready to use. However, you just need to state that this stage in the course needs to be activated once the subscriber enroles. Chose Wait 1 day and change the interval to 0 days and chose Set new interval and the stage is now send immediately when a new subscriber registers.
The course is now ready to be activated. In the top left corner you will see Start automatically for new subscribers on the list --> select it, once this has been done a notification will pop up - once read, select I understand --> In the bottom right corner you will see Activate course select it and the course is now activated. You can test it by enrolling yourself to the list and by confirming you enrollment. If everything has been set correctly you should receive a welcome email.
If you are importing you subscribers to your list they will receive the welcome e-mail unless you deactive the course and remove the confirmation in Start automatically for new subscribers on the list before you perform the import.
If you do not remove the confirmation once the the course has been deactivated, the subscribers you import will still receive the welcome email.