1. Installation 1. Installation Sources
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1: Deploying and Managing Windows Server 2012
Installation
1. Installation Sources
5. Installing Windows Server 2012 R2 Core and GUI
6. Upgrade to Windows Server 2012/R2
7. How to migrate servers – relate it to new installation or parallel installation

2. Installation Source (Physical/Virtual)
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1: Deploying and Managing Windows Server 2012
Installation Source (Physical/Virtual)
Nowdays, most of the build process is done on Virtual Machines, and ISO is the most commonly used. Still for a physical server installation, USB is sometimes not recommended in organizations because of it’s RAM nature.
Network install not only includes .WIM file, it also supports .VHD and .VHDX.
ISO
Disk Drive
USB
WDS/MDT/SCCM

3. Types of Installation

4. Upgrading Windows Server
It sound very simple to do.
There can be unforeseen complications.
It retains all the complicated settings and configurations while just making the operating system newer.
Rollback options will generally require re-installing the original configuration.
This requires consistent backups, and the expertise to restore them immediately if things go wrong.
Clients need to carefully research the available upgrade options.  For example, cross-architecture upgrades are not supported. Which means businesses can’t move directly from 32-bit Windows Server 2003 systems to 64-bit Windows Server systems. Customers in this situation cannot upgrade and must do a fresh install.
Best For: Environments where the budget is tight; places with complicated in-house applications and cross-server installs and configurations that might be difficult to recreate with new hardware.

5. Install New Servers Also known as the Parallel Environment method
With the Install New Servers Approach, a company will purchase new servers to host the upgraded operating system.
IT organizations will often use this opportunity to increase the power of existing server hardware.
Typically, the business will install a clean operating system on the new servers and then transfer the roles, applications and workloads off of existing servers, shutting down server as their responsibilities are offloaded.
While it is conceivable, a company could replace every server one-for-one, most enterprises will take advantage of virtualization to consolidate servers on more powerful hardware when possible.
Best For: Data companies looking to get clean installation of operating system, or looking to consolidate servers. Most cautious approach.

6. Partial New Servers
Just because the operating system is a decade old doesn't mean all of the servers are.
In many cases, some of data center hardware is still sufficient and there is no need to replace it all.
In that case, the IT organization may choose to bring in a limited amount of new hardware, and continue using existing servers where it makes sense.
Using the same methodology as above, functions are replicated from existing servers to the new hardware. Old hardware that will no longer be used is retired as workloads are transferred. With this method, there is an additional step of upgrading the existing hardware to Windows Server 2012.
Best For: Environments with plenty of existing hardware with sufficient capability to run Server 2012, companies looking to consolidate server hardware.

7. Migrating Server Roles & Features to 2012
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Migrating Server Roles & Features to 2012
1: Deploying and Managing Windows Server 2012
Migration documentation and tools ease the process of migrating server roles, features, operating system settings, and data from an existing server that is running Windows Server 2003, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, or Windows Server R2 to a computer that is running Windows Server 2012 R2. By using migration guides using below link
Not all Roles can be migrated. The link is the best place if you are looking for migration of Roles and Features.

8. Minimum Requirement Component Minimum Requirement Recommended Maximum
Processor
1.4GHZ 64-bit
2GHZ or faster dual core
Not applicable
Memory
512MB RAM
2GB RAM or greater
32GB RAM Standard Edition4TB RAM Datacenter Edition
Disk space
32GB
40GB Full installation or 10GB Server Core installation

9. Installing Windows Server 2012
Please refer to Windows Server 2012 Installation steps from the document.