The most basic way is to login to 1Shoppingcart, and send manually from there (although you can also subscribe them using a web form).
It depends if the contact is already in the database. If they are not, you'll want to add them by following this article
Assuming the contact is already in the system, find the contact under "manage contacts"
Type in their name or email to find the contact and hit the "search" button.
From the search results page, you can subscribe the contact(s) to an autoresponder campaign. If there is more than one person, you can choose to un-check their checkbox which will exclude them from the action.
Alternatively, if you want to edit/view the client's info before subscribing the autoresponder, then click on the name of the contact. That will open up the contact's full information. After you've reviewed the contacts info and made any necessary changes, you are ready to subscribe the autoresponder(s). Click on the "autoresponders" tab.
simply click on the "Autoresponders" tab. Please note, you'll first need to enter the person's name and email and hit "Save" in order for any of the other tabs to work.
Next, click on the "Subscribe to New Autoresponder" button
Now, choose the autoresponder you'd like to subscribe this contact to and hit the "Save" button and you're done!