Push Deployment Wizard is available inside Symantec_Endpoint_Protection_12.1_Tools_and_Documents_EN.exe.
Symantec_Endpoint_Protection_12.1_Tools_and_Documents_EN.exe could be download from https://fileconnect.symantec.com

Once Symantec_Endpoint_Protection_12.1_Tools_and_Documents_EN.exe is downloaded, unzip the contents to any directory of your choice.

Push Deployment Wizard helps to deploy client software by pushing the client software to remote computers and automatically installing it.
You would need Administrator rights / privileges to the windows domain to which the client computers belong or to the computers themselves, if they are in workgroups.
Push Deployment Wizard is used when installing clients on a Remote Location where you have few systems but the bandwidth between 2 locations is very low and you are unable to install all the clients at one time.

Here are the steps in how to use the same.
- Create a relevant Package for the Environment as .EXE (Please Make Sure the file name should be setup.exe)
- Copy the PushDeploymentWizard Folder From the Tools directory of the SEP software disc.
- Move the Package and the PushDeploymentWizard Folder to any 1 system at the Remote Location which is connected to the internal Network
Steps to be performed at the Remote Location (These steps can be performed using RDP session or ask somebody to perform the steps)
1. Select 1 system on which we have both the files.
2. Double Click on ClientRemote.exe
3. Click Next

4. The 1st option "Deploy Symantec Endpoint Protection full install or patch" is used when you have the full SEP installation package or incase if you had downloaded the "client patch" from https://fileconnect.symantec.com (check below to understand "client patch")

Whereas, "Deploy self-installing executable" would be used when you want to push the .exe using command line reference for Symantec Endpoint Protection 12.1, check the documentation of Implementation_Guide_SEP12.1.pdf - Appendix B (Customizing and deploying the client installation by using third-party tools) on page 1003, then page 1008-9 in particular for the component names.
5. Specify the Maximum number of concurrent deployments.
6. Once, selected the correct option, Click Browse and Specify the Folder containing the client Software
7. Select the Computers in your Network or Create a list of IP address or host name and save it in a Notepad File and Click on Add or Import Computer and provide the file containing the host name and IP address.
8. Click Finish
NOTE: There is a difference between Push Deployment Wizard available in SEP 11.x and SEP 12.1. However, both are meant for same purpose.
Remote Push Deployment Wizard could be used as an alternative to Client Deployment wizard.
Here are Links to the Patches.
Symantec Endpoint Protection 12.1 RU1 Client-only patch
http://www.symantec.com/docs/TECH174706
Also, check the same on https://fileconnect.symantec.com