SAP SRM(Supplier Relationship management) installtion

Dear All,

I am very new to SAP SRM ,we need to install SAP SRM system,i have checked in the service latest veriosn is SAP SRM 7.0 EHP3.

I ma having confusion while checking the media in service market place below location

Installations and Upgrades - S"SAP SRM"SAP SRM ENHANCE PACKAGE"EHP3 FOR SAP SRM 7.0 we have 3 options

• Installation and Upgrade 
  • Microsoft SQL-Server 
  • ORACLE Database 
  • SAP HANA
• Application Help (SAP Library) 
• SAP NETWEAVER 7.4 

we need to slect for the medi download for both the options ( SAP NW 7.4 and installtion and upgrade ) or only option .

Please calrify below points as well

1)what is the usage type for this application?(SRM)

2)which scenario it is required.

Please suggest and guide me