How to change header section text value at runtime, using C sharp 2010

Please I need help

1 - I Have a C# Form named u201CForm1u201D

2 - I added a crystal Report Viewer u201CcrystalReportViewer1u201D to u201CForm1u201D

3 - I linked the u201CcrystalReportViewer1u201D to an empty Crystal Report named u201CCrystalReport1u201D

4 - I added a Text Object named u201CText1u201D to the Header section of the report u201CCrystalReport1u201D

5 - I put the text u201CAu201D in the text property of u201CText1u201D

6 - I run u201CForm1u201D, u201CCrystalreport1u201D blank report with u201CAu201D is perfectly displayed

7 - I need to change at runtime u201CText1u201D from u201CAu201D to u201CBu201D

How and where to write the C# code?