SessionOptions sessionOptions = new SessionOptions
{
    Protocol = WinSCP.Protocol.Sftp,
    HostName = "t-4c0g77558b264asdf.server.transfer.us-east-1.amazonaws.com",
    UserName = "username",
    SshPrivateKeyPath = "C:/FOLDER/DIRECTORY/.ssh/Key",
    GiveUpSecurityAndAcceptAnySshHostKey = true,
    PortNumber = 22,
    SshHostKeyPolicy = SshHostKeyPolicy.GiveUpSecurityAndAcceptAny
};
 
using (Session session = new Session())
{
    session.SessionLogPath = "C:/FOLDER/DIRECTORY/.ssh/log";
    session.DebugLogPath = "C:/FOLDER/DIRECTORY/.ssh/debug";
 
    try
    {
        session.Open(sessionOptions);
    }
    catch(Exception e)
    {
    }
}