How to organize an APP page

Very new to Powershell Universal ...as in got it installed this week.  We are still using an unlicensed version until I can prove out that it can do all that we need done.

The first thing I'm working on is an APP that will collect parameters to be fed via Invoke-PSUScript to an automation Script.  

I am figuring that part out fairly well.

What I can’t figure out is how to organize the actual app webpage.

My example dummy script so far

New-UDApp -Content {

 New-UDSelect -ID "Number" -Label 'Number' -Option {
 New-UDSelectOption -Name "One" -Value 1
 New-UDSelectOption -Name "Two" -Value 2
 New-UDSelectOption -Name "Three" -Value 3
}
 New-UDSelect -ID "word" -Label 'word' -Option {
 New-UDSelectOption -Name "One" -Value "Hello"
 New-UDSelectOption -Name "Two" -Value "GoodBye"
 New-UDSelectOption -Name "Three" -Value "No one is home"
}
 New-UDButton -Text "Run Script" -OnClick {
  $value = (Get-UDElement -ID "Number").value
  $value2 = (Get-UDElement -ID "word").value
  Invoke-PSUScript -Name "test.ps1" -value $value -word $value2 -Integrated -Wait

} -ShowLoading
}

So in this case when i “view app” it just stacks Number / Word / Run Script (click button) next to each other.

I assume there has to be a way that I could say place "Number in top left of page, Word in top right and ‘Run Script’ click bottom in bottom left.

How do you say where things go rather than just letting them stack up next to each other?