A Prerequisite Opportunity is one that a volunteer is REQUIRED to sign up for in order to signup or express interest for another opportunity.  (Example: You require volunteers for a painting project to also attend the prerequisite 'painting training' opportunity.  They will be unable to sign up for the opportunity unless they also signup or express interest in the training OR have attended that prerequisite in the past.  

When a volunteer signs up or expresses interest in an opportunity that has a prerequisite, they will be also automatically be directed to signup or express interest in an occurrence the prerequisite opportunity

NOTE:  Because of the complexities of team signups, prerequisites are not compatible with the team signup process.  If an opportunity requires a prerequisite, and a volunteer signs up as part of a team, they will NOT be automatically redirected to signup for the prerequisite opportunity as well.  We recommend that you turn off team signup for any occurrences that are part of a volunteer opportunity that requires a prerequisite.  See this link to enable the functionality to "turn off team" if it is not present in your occurrence records.   Alternately - you can monitor when a team captain makes a connection - and contact them, telling them they need to sign up each team member for the prerequisite opportunity as well.

Just because you can add as many fields as you want to an object - it doesn't mean you should. The power of a relational database comes in being able to see related objects in the page view - so you don't want to add too many extra fields with lookups in the record detail itself.

If you want to see a lot of different fields from different objects in one place, create a report!

But what do you do you do if, for example, you want to start keeping track of tools that are being used at different occurrences? Do you add fields to keep track of the tools?

NO. To fully leverage the power of a relational database you would create a new object: Tools.

This article details the steps taken by System Admins to enable the Batch Create Functionality for Team Members and Connections.

NOTE: The ability to batch create Team Members and Connections while making it easier to complete these steps have the potential to corrupt or duplicate your data. System Admins should only enable these features for trained users. It is not recommended that you enable this feature for Partner Staff. If desired you can use permission sets to enable it for designated staff and partner staff users.

To learn more about permission sets, see this Salesforce post

When a staff member at a partner staff leaves their position, and no longer should have access to their partner portal, you need to perform a couple of steps to do this.