Stand in the room that you are trying to anchor to. Type @open <your exit name>=<your room number><enter>
If you were successful, you will have a message like "Exit your-exit-name opened. If not, the most common error message is "Permission denied." This means the room you are in is not set for new links by a non-owner. You have to talk to the owner to fix this.
Get the number of the room you are in, then use your new exit. Type @open <out>=<Anchor room number><enter>. Again, if there is an error, it is probably the destination not being properly set. Did you include a #? Is the destination still open to being linked to?
Now we rename your exits. It gets boring fast when you have to type "living room" everytime. So we add some aliases. If you type @name living room=(Li)ving room;living room;living;li<enter> you will see the exit (Li)ving room, but will be able to use it by just typing li.
You can do this at the same time you @open the exit the first time. The form is: @open (Li)ving room;living room;living;li=<your room number><enter>
One cautionary, and one suggestion. First, don't use just 'L' as one of an exit's names. Someone will want to take a look at the room and find him/herself outside it! And always add out;o to one of the exits, so someone can escape by just typing 'out' over and over again. It's more fun to explore if you can get out again without resorting to teleportation.
From here, it is fairly simple to @dig, then @open. Drawing a diagram first might be of use. Having a scratch pad to note room numbers is a good idea.
editroom is a program that can help you tidy up the place.
Personally, I try to write a room description without using "you see." You have to be especially careful not to sy "on your left" unless there is only one way into the room.
Coming soon: adding detail without clutter: the "look #edit here" utility.