Copy last modified files from network path into SQL server box and rename them using Agent job
Found a work around : 

I have created ps1 file using the script below....
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$source = ''
$destination = ''

@(Get-ChildItem $source -Filter *.bak | Sort LastWriteTime -Descending)[0] | % { Copy-Item -path $_.FullName -destination $("$destination\CMSOPEN_backup.bak") -force} 
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and then, created bat file which calls this ps1 file, went to sql agent job, created step to execute the bat file later executed the t sql for restore.