Follow these steps –
Import-AzurePublishSettingsFile yourpublishsettings.publishsettings and set your azure account
Get-AzureSubscription (this will give you the list of subscription)
then finally select the subscription name you want to use
Select-AzureSubscription <subscription-name> will set the current subscription but not make the default one, so this change will be gone when you open powershell again next time.
If you’d like to change the subscription across sessions, use Select-AzureSubscription -Default <subscription name>