Install AzureAD Module and connect:

Install-Module -Name AzureAD
Import-Module AzureAD
Connect-AzureAD

Assign usage location:

Set-AzureADUser -ObjectID User@domain.com -UsageLocation "NL"

Get license plans for your tenant:

Get-AzureADSubscribedSku | Select SkuPartNumber

Assign Office 365 license to user:

$userUPN="User@domain.com"
$planName="O365_BUSINESS_PREMIUM"
$License = New-Object -TypeName Microsoft.Open.AzureAD.Model.AssignedLicense
$License.SkuId = (Get-AzureADSubscribedSku | Where-Object -Property SkuPartNumber -Value $planName -EQ).SkuID
$LicensesToAssign = New-Object -TypeName Microsoft.Open.AzureAD.Model.AssignedLicenses
$LicensesToAssign.AddLicenses = $License
Set-AzureADUserLicense -ObjectId $userUPN -AssignedLicenses $LicensesToAssign

Connect to Exchange Online:

Import-Module ExchangeOnlineManagement
Connect-ExchangeOnline -UserPrincipalName admin@tenant.onmicrosoft.com

Set Mailbox Regional Config:

Set-MailboxRegionalConfiguration -Identity "User@domain.com" -Language nl-nl -LocalizeDefaultFolderName -TimeZone "W. Europe Standard Time"