Hi,
You can use Remote Push method: Remote Push performs the following actions:
Selects an existing client installation package or creates a new installation package.
For new installation packages, configures package deployment settings.
Locates the computers on your network.
Remote Push locates either specific computers for which you provide an IP number or range, or all computers that are visible by browsing the network.
Pushes the client software to the computers that you specify.
The installation automatically begins on the computers once the package is successfully pushed.
Reference: Deploying clients by using Remote Push
You can refer these articles as well:
About client deployment methods
http://www.symantec.com/docs/HOWTO81302
Steps to prepare computers to install Symantec Endpoint Protection 12.1 client
http://www.symantec.com/docs/TECH163112
How to prepare computers for remote deployment
http://www.symantec.com/docs/HOWTO16365