Just installing the hubspot tracking code on my website. Will the forms auto-capture the informations and create a unique contact id?
If you are using external forms rather than embedding HubSpot forms then you need to set up your system to actually collect the values being captured as outlined in this article.
Will it automatically tell me the which pages they've visited? I don't see that yet.
This information will be available only if HubSpot can link a cookie to the submission, read more here
Other than the installing the code, should subscribe to content traffic reporting to actually understand this?
It's my understanding that for traffic reporting you would need a higher subscription as you can see here. I think that the setting linked in the first section might be the answer though.