New to MacBook Pro:

Macs don't need or come with AntiVirus software, leave your Windows habits with the Dell. They also don't need defragmenting, optimizing, cleaning or any other of the dizzying array of stuff that Windows does (and even it would be better off without most of them)

Just use it, don't let the battery go flat, don't get it wet. That's about it.

You will need to discard your Windows habits, they are not at all productive on a Mac and some are downright risky.

Just use it, and your common sense (i.e.: if you get an email telling you that you have won a million dollars and Christy Turlington is going to deliver it personally, it's a fake, don't call)

Best advice?

Institute a backup routine, Time Machine is good for that.

Good read > Viruses, Trojans, Malware - and other aspects of Internet Security: Apple Support Communities

If you install anti virus software on your Mac, you may encounter problems. A majority of Mac users that install a/v software come here to ask for uninstall instructions.

Make sure Gatekeeper is enabled.

Click your Apple  menu top left in your screen. From the drop down menu click: System Preferences

Then select Security & Privacy then select the General tab.

Make sure: Mac App Store and identified developers is selected. If that area is greyed out, click the gold padlock icon. Enter your admin password then you can select: Mac App Store and identified developers

OS X: About Gatekeeper