Goto Related record from a Portal

[Rfox]

The idea is simple. I just don't know how to make it work.

The database has 3 main fields: ID Number, First Name, Last Name

It is for inputing a name to get the related ID Number.

It is for children to use so I want it to operate as simply as possible.

The first page I have them Type their First Name. It does a simple find.

The second page I want to display a list of all last names that match the first name. Then they could choose - click on - put an X by - something -- the last name and it would continue to the related record and display the ID Number.

I created a portal to display the last names, but I do not know how to allow selection of a record from a portal.

Thanks for your help. Or if another approach is better, I'm open. I was having them type the first 4 letters of the last name and then completing the search - but I thought the idea of CHOOSING a last name from a list would be simpler.