is there a place to find a resource's required configuration identifies?

this is the corrected code = after following the answer below,

but i wanted to post this for any other Powershell users out there...

                                 
    virtual server creation      
                                 


$snap = @{}
$snap.Add('type','automap')
$snapp = $snap | convertto-json

$profile = @{}
$profile.add('kind','ltm:virtual:profile')
$profile.add('name','http')
$profile.add('partition','Common')


 check to see if vs is already created
$uri = "https://$f5ip/mgmt/tm/ltm/virtual/$vs"
reset err value
$err = $false
try{$resp=Invoke-WebRequest -Method Get -Uri $uri -insecure -Headers $headers -Credential $credentials}catch{$err = $_.Exception}

if($err.Response.statuscode -match 'NotFound')
{
    write-error 'returned a 4xx, virtual server must not exist'
     create https vs
    $URI = "https://$f5ip/mgmt/tm/ltm/virtual"
    $rules = @("_sys_https_redirect")

    $body = @{"name"="$vs";
        "partition"="Common";
        "rateLimit"="disabled";
        "ipProtocol"="tcp";
        "source"="0.0.0.0/0";
        "destination"="${stgvip}:443";
        "mask"="255.255.255.255";
        "description"="autocreated $vs";
        "pool"=$PoolName;
        "profiles"= @($profile);
        "sourceAddressTranslation"=$snap}

    $JSONBody = $body | ConvertTo-Json 
    $newvirtualserver = invoke-webrequest -Method POST -URI "$URI" -Insecure -Body $JSONBody -Headers $headers -Credential $credentials
}else{
    write-error 'server already exists'
}