After installing the extension, press the Metamask icon at the top right of your screen
and you will see the following screen:
and you will click on: Continue
Then you must create a password (secure) and click on: Create
Click on Reveal secret words.
You will see a phrase that contains 12 words, which you must save in a safe place and press next
You must verify the phrase generated previously, at the end click on confirm.
Congratulations, You have successfully created your MetaMask account.