Those requirements are a bit vague. Are you running a select statement? An update? What will your CSV look like?
Here is some boilerplate PowerShell code to help you get you started interacting with your CMS.
$serverGroupPath = 'SQLSERVER:\SQLRegistration\Central Management Server Group\<GroupName>\'
$instanceNameList = dir $serverGroupPath -recurse | where-object { $_.Mode.Equals("-") } | select-object Name -Unique
foreach($instanceName in $instanceNameList)
{
# do something against each server here
}
There are no special teachers of virtue, because virtue is taught by the whole community.
--Plato