You can open the command line and get the help on it by:
net use /?
Anyhow here is an example of the context that you wanted to use:

"net use_\\computername\sharename\volume_password_/user:domainname\username_password"
Legend: Bold characters are non-variables, it doesn't change. The others you substitute with whatever is applicable to you.
First password is for the share (if there is one), the second one is for the user(again if applicable).
I used the "" for wrapping purposes so if the command interpreter (system) is not configured to support long file names, this would help the command to remain valid and work even in a batch file.

Each underscore needs to be replaced with a single space!!

A very good alternative freebie you could use is Mapper24 0.2.3

I hope this helps.