I assume that by reading the folder you mean reading emails from this folder. You do this in the same way as you would do with any other folder - use Imap.Select method.
Some additional points:
- '/' is not necessarily path delimiter. Some IMAP servers use dot char ('.') for that.
- If '/' is a hierarchy delimiter, creating such folder (e.g. "foo/bar") for the server should be equivalent to creating "foo" folder and a child folder named "bar" (RFC 3501 section 6.3.3).
Here's the code:
using (Imap imap = new Imap())
{
imap.Connect("imap.example.com"); // or ConnectSSL for SSL
imap.UseBestLogin("user", "password");
imap.Select("INBOX/folder1");
Console.WriteLine(
"There are {0} messages in 'INBOX/folder1'",
imap.GetAll().Count);
imap.Close();
}