Purview Account

Just started using Purview and can see that data in my MS cloud has already been categorised and when I create new files they are categorised too.  But I do not have a Purview Account - do I need one ?

I do not see the Data Map menu despite reading articles about putting my account in various groups but now wandering if its because we do not have a Purview Account.

If i created a new SIT I would have to go to each SharePoint site and have re-index it which I would prefer to have it done to all sites at once which I believe you can do in the Data Map which we cannot see.