How to create the package from SEPM to install the client for unmanage?
See this article
How to create an Unmanaged client from within the Symantec Endpoint Protection Manager
Check the attach article
How To: Create an unmanaged client install package from the SEPM with custom policies.
Also you can find unmanaged client in file connect
To install an unmanaged client:
Hi Please follow the belwo mentioned steps to create a unmanaged client:
1) Open the Symantec Endpoint Protection Manager >> Go to the admin tab at the bottom
2) Click on Install packages
3) Right click on the 32 bit or 64 bit package accordingly and select export
4) Now under the Export folder, Select a folder where you want to export the package
5) Under installation settings select Default client installation settings and under Security features, select the feature set you would like to install. Full means all available features will be installed, Basic means only Virus and Spyware Protection will be installed
Directly below the Security Features drop down menu is a Select button. When clicked, this will allow you to specify whether you want all available updates to be applied at time of installation, or the client will download updates after installation. The difference in set-up file size is approximately 100-120MB.
6) Under Export settings select - Export an Unmanaged client and uncheck export packages with the policies from the following groups and now it should be grayed out
7) Preferred policy mode - Select Computer mode
Now click ok and the package would be saved on the selected location and you can now install it
Refer the article below
Plz go through with below article..this is simple to understand.
Creating an installation package for unmanaged clients with custom policies.