You need to buy the SIM card. You can go in any Bell store to get it. It should take a few minutes (you'll have to open up the phone for the guy to enter it's IMEI and he will print out a tree worth of paper for you to sign).
Make sure you in a place with great reception. Put the SIM in the phone and boot. You'll have bars, but no 3G. You need to manually enter the APN (inet.bell.ca) I think there is an option or you'll be asked when the phone can't get any data connection (don't remember exactly how it's done, but it should be close to obvious).
After your profile is activated, the phone will start restoring it and will download all your apps.
Note that you better install Save/Restore (you need Preware to install it) and backup your apps data of your old phone, copy the saverestore folder to a PC) as the Palm Profile does not store all of your apps data (just the Palm apps and even then, it does not backup text messages and some other stuff). Once your apps are restores, open each of them and close them. Then load Preware and Save/Restore, copy the saved files from your computer and restore them with Save/Restore (Homebrew documentation app is your friend here if that's not clrear enough).
If some of your apps do not restore it's because they are not compatible with webOS 2.1. You can't do anything about it (but there should not be a lot of apps in that situation).
As soon as you can, I suggest you System Updates and verify if webOS is at the latest version.
You should have access to paid apps.