redirect iweb page to another page of my own within the same site.

[pen.cap.chew]

Hello,
really hope i've posted this in the correct place, but if not i apologise.

Ok, so i'm currently developing a website for a university assignment. The site does not need to be properly published and active on the net - just published to a folder and handed in on a disc.
I am not experienced with web design AT ALL but am doing ok so far, there are just a few things that i would really like to incorporate that i'm not sure how and so hopefully someone here can help:

1. I would like my 'intro' page to automatically redirect to my 'welcome' after approx 15 seconds (as there is a musical jingle and animated logo that appear on the intro page that i'd like people to see before being taken to the next page).

2. I would like a thumbnail i have created to open a larger version of the picture in its own window without having to create a page within the site on which the larger version can be viewed. Not sure i've explained properly so hopefully the following pictures will help make sense of it:

So i'd like to be able to click this -

>

and have it enlarge like this in its own window.

Any help will be greatly appreciated. And please bear in mind that i'm no dab hand with this whole thing so as simple an explanation as possible would be much more helpful.

thanks a lot.