>>>I am installing SQL Server 2008 R2 Express on customer server. But I don't see anywhere the option for SQL server management studio.
>>>
>>>The Installation Center has the following items:
>>>Planning
>>>Installation
>>>Maintenance
>>>Tools
>>>Resources
>>>Advanced
>>>Options
>>>
>>>But I can't seem to find SSMS anywhere. Which of the items above should have it?
>>>
>>>TIA
>>
>>Check in the Tools section. Also, which package did you download? It should be the one with Advanced Services. This includes SSMS for sure.
>
>Neither Tools no Advanced has SSMS option.

You misunderstood me. Which msi package you're using? Did you download the one named 'SQL Server Express with Advanced Services'?

You should either download this one or the one with Tools. Otherwise the basic SQL Server Express msi does not have Tools which include SSMS.