Go to Microsoft account and select Sign in. 

Type the email, phone number, or Skype sign-in that you use for other services (Outlook, Office, etc.), then select Next. If you don't have a Microsoft account, you can select No account? Create one!. Note that we recommend using an email you already have and use regularly.

Type your password and select the Keep me signed in box if you want to go straight into your account next time (not recommended for shared computers).

Select Sign in.