When you first login into your new account it is best to check under "preferences". You want to be sure 'User Level' is set to "high". This will give you all the functionality of webmail. Be sure your Email Address is your userid + @uregina.ca. You can customize colour schemes, etc. If you want to save a copy of each email you send then you will need to create a folder for this. See Question 2.
Folder creation requires a prefix to the name of the folder. As in Question 1, where you will a folder to store your sent message, say "sentmail", you would use "INBOX.sentmail" for the name of the new mailbox. Because WebMail utilizes the IMAP protocol of the email server, you can create hierarchies of folders. For instance, if you wanted to use "sentmail" to store your outgoing email but wanted your 2004 outgoing to be "archived" but archived under "sentmail" then you could create INBOX.sentmail.2004. INBOX.sentmail must first exist and you will have to move the email items from sentmail to sentmail.2004. Such hierarchies go a long way in keeping the WebMail interface on one screen.
Complete email deletion is a two step process - mark for deletion and then expunging. Marked for deletion will show a Red X beside the targeted email. Expunge then tells the server to actually do deletetion. When User Level is not High, the expunge icon is not visible and complete deletion can't be done See Question 1.
WebMail, for the most part, is just an email client via the web and accessible with any browser, anywhere there's internet connectivity. Using WebMail doesn't preventing a user from using other methods to access the email store, but, depending on the connection and location, other email clients may have trouble sending email. Using an ISP that is unknown to the email server results in a "relaying not allowed" error for sending email. Known ISPs are SaskTel and Access. Because the WebMail server is known by the Email server, such errors never occur even though the user may be in Australia.
New users will notice their account has a folder called "spam". Our email filter server tags spam email coming into the email server and delivers it to the "spam" folder rather than your INBOX. Every night email in the "spam" folder that is older than 21 days is deleted. Best to check the folder periodically. New accounts are less likely than aged accounts to accumulate spam email.