Real quick, let's take a look at how to use OpenCore.

Reboot your Mac, and hold the Option (alt) key while starting up.

Your startup manager may look something like this:

Choose the "EFI Boot" option. Click the arrow pointing up to continue.

When OpenCore boots, you will be greeted to a new boot manager looking thing. Here, choose the drive you wish to start your Mac.

If you have a 2012 or older, your boot manager will be a grey instead of black. Unfortunately, OpenCore by default loads in this dark boot. So, you'll see the light grey screen, the dark boot manager, and then a dark screen with the white Apple logo. Yes, there is a way to fix this, but it will require some text editing, which we'll cover later.

If you have a 2013 or newer, the Mac will always boot in this dark mode.

I will be making a guide to where you can customize the OpenCore boot picker screen, add custom icons, and so much more later on. This guide will actually become available soon.