Unable to Create Multiple Parameter Connections in BimlStudio

How to add multiple parameters?     

You can add as many parameters to the expression as you want, and simply add more calls to your Project settings. Let's say you wanted to parameterize both DataSource AND initial catalog in your Connection String you would do something like this:

<Expressions>
<Expression ExternalProperty="ConnectionString">"Data Source=" + @[$Project::ServerName] +";Initial Catalog=" + @[$Project::InitialCatalog] +";Integrated Security=True;" </Expression>
</Expressions>

Where "InitialCatalog" and "ServerName" are the property names that you wish to pass in.

I can add multiple Expressions for each parameters but what values should we input in the target, if I have multiple project parameters?

<#@ extension bundle="BimlFlex.bimlb" extensionpoint="ConnectionExpression" target="" #>
<#@ property name="connection" type="BimlFlexModelWrapper.ConnectionsWrapper" #>
        
You need to create Connection Expression.biml for each Project Parameters.