The next screen is the Sign in to your PC step.
You have two pretty big options here for how to sign in with Windows 8:
Sign in with your Microsoft account
If you already have an email associated with a major Microsoft service then you can use that here. If you don't, that's OK, enter any email address and Microsoft will create an account for you based on that email address.
The advantage of using a Microsoft account is that you can easily use the Windows Store, you can sync major settings between multiple Windows 8 computers, and more.
Sign in with a Local account
Your account is only stored locally on this Windows 8 computer. Please note though that you'll still need to create a, or use your current, Microsoft account some time in the future if you plan on using the Windows Store to download apps.
My recommendation is to use your existing Microsoft account or create a new one.
Assuming you decide to do that, enter your email address and then click or press Next.
The next several screens (not shown) will verify your account, ask for your password, and may ask for a telephone number or other information to help with password recovery. If you're setting up a Microsoft account for the first time, you may see some other screens as well. If you're signing in with an existing account, you may be asked to confirm a code sent to your email or phone, copy settings and apps from other Windows 8 computers, etc.