Confused about domain names

I’m doing webdesign and design in general since a long time, but that’s the first time I try to actually set up the webspace and domain name myself…And I am completely lost!

I got my domain name from directnic…And a friend lended me some webspace on networksolutions…I tried to get help from directnic on how to get my domain name to point to a subfolder of networksolutions, but to no avail. They instructed me to redirect traffic going to my domain name to the subfolder. They keep the site in a frame, so the browser location doesn’t change…But that’s not what I want! I don’t want my site to be in a frame! I just want the freakin address to point to that subfolder. Why is it so hard?
Even harder: e-mail adresses…I can create several e-mail adresses at networksolutions but all I can do at directnic to handle e-mails is also to forward them…
I don’t get it.

  1. Why can’t I just instruct the DNS servers to have “www.mydomain.com” (bought on directnic) to point to “www.myfriendwebsite.com/mydomain” (hosted on networksolutions)?
    and
  2. Why can’t I instruct all emails sent to "adress@mydomain.com" to use the mail servers of networksolutions?

Both companies aren’t answering my questions
I don’t know if I am actually expecting an answer here, just stating the fact that these big companies don’t like you to not buy a whole package and provide no feedback to someone who doesn’t want to do it.
Any clarification would be appreciable.