I would recommends you create a new environment and migrate your data/site into that environment. With 9.1 beyond xConnect you have identity server all all the configs that tie it together.
This file will set up all the parameters for xconnect install. Just change the name and paths to what you need.
Install-Xconnect-tasks-parameters.ps1
#define parameters
$prefix = "sc91"
$PSScriptRoot = "C:\resourcefiles"
$XConnectCollectionService = "$prefix.xconnect"
$sitecoreSiteName = "$prefix.sc"
$SolrUrl = "https://solr:8983/solr"
$SolrRoot = "C:\solr\solr-7.2.1"
$SolrService = "Solr-7.2.1"
$SqlServer = ".\SQLEXPRESS"
$SqlAdminUser = "dev"
$SqlAdminPassword = "dev123"
$IdentityServerSiteName = "$prefix.identityserver"
$ClientSecret="Random_STRING"
$SitecoreAdminPassword = "b"
#install client certificate for xconnect
$certParams = @{
Path = "$PSScriptRoot\createcert.json"
CertificateName = "$prefix.xconnect_client"
}
#install solr cores for xdb
$XconnectsolrParams = @{
Path = "$PSScriptRoot\xconnect-solr.json"
SolrUrl = $SolrUrl
SolrRoot = $SolrRoot
SolrService = $SolrService
CorePrefix = $prefix
}
#deploy xconnect instance
$xconnectParams = @{
Path = "$PSScriptRoot\xconnect-xp0.json"
Package = "$PSScriptRoot\Sitecore 9.1.0 rev. 001564 (OnPrem)_xp0xconnect.scwdp.zip"
LicenseFile = "$PSScriptRoot\license.xml"
Sitename = $XConnectCollectionService
XConnectCert = $certParams.CertificateName
SqlDbPrefix = $prefix
SqlServer = $SqlServer
SqlAdminUser = $SqlAdminUser
SqlAdminPassword = $SqlAdminPassword
SolrCorePrefix = $prefix
SolrURL = $SolrUrl
}
This file kicks off the parameters you specified above.
Install Script
. $PSScriptRoot\Install-Xconnect-tasks-parameters.ps1
Install-SitecoreConfiguration @certParams -Verbose
Install-SitecoreConfiguration @XconnectsolrParams
Install-SitecoreConfiguration @xconnectParams