How to add Reporting services sharePoint features in SQL Server 2008R2 I am facing some issues related to SSRS on SQL Server 2008R2, 
how can we have install below features:

Reporting Services- SharePoint

Reporting Services Add-in for SharePoint Products

Any one could you please help me.

Thanks
The Microsoft SQL Server 2008 R2 Reporting Services Add-in for Microsoft SharePoint 2010 products is installed by the SharePoint 2010 Products Preparation tool (PreRequisiteInstaller.exe). If you want to download and install the add-in separately, the most up-to-date version of this file is available online at the Microsoft Download Center [1]

Download the add-in From https://www.microsoft.com/en-in/download/details.aspx?id=622 and follow the instructions

Step 1: Install a SharePoint technology instance.

Step 2: Install SQL Server 2008 R2 Reporting Services and specify that the report server use SharePoint Integrated mode.

Step 3: Configure Reporting Services.

Step 4: Download the Reporting Services Add-in by clicking the rsSharePoint.msi link later. To start the installation immediately, click Run. To install at a later time, click Save.

Step 5: Install the Reporting Services Add-in and configure the report server on the SharePoint technology instance.

Step 6: Set permissions and add Reporting Services content types.

Step 7: Verify the installation. 

Detailed version : https://msdn.microsoft.com/en-in/library/aa905871.aspx

Known Issues, Another useful link