Mongodb c# a query with multiple Conditions from many collections

Question

As a newbie to Mongodb am facing this problem to query from different collection based on conditions from those collections and not just one:

I'm actually recieve a user email as a query request to my Rest API, this user can be either linked to a personnel Account or to a company Account.

In this case I want to retrieve all the company that are Active for a user having the email from my token and the user.LinkedEntity == "Company" and user.LinkedEntityId == CompanyId

public class User
{
    public int Id { get; set; }
    public string Email { get; set; }
    public string LinkedEntity { get; set; }
    public string LinkedEntityId { get; set; }
}

public class Person
{
    public int Id {get; set;}
    public int Name {get; set;}
}

public class Company
{
    public int Id {get; set;}
    public string Label {get; set;}
    public bool Active {get; set;}
}