Can't seem to do anything but archive mails- actually I want to delete them. iPad 1

I assume that it's a gmail account, in which case you can change the archive icon to a trashcan via the account's settings in Settings > Mail, Contacts, Calendars : http://support.apple.com/kb/HT4207

In Mail/Preferences/Accounts click the Account, then click Maibox Behaviors, set the Trash entries as follows

check the "move deleted messages to the Trash Mailbox",

check "Store deleted messages on the server"

in "Permanently erase deleted messages when:" you can set when you want them to disappear.

Brian, this was for the settings in your iMac. After rereading I saw that you ask it for iPad. Do as the Penguin says.