Customizing Themes & category pages

Hi,

I am new to WordPress, & am trying to create a modestly ambitious website with my installation. I can’t seem to figure out a few things, can someone point me to clear precise info about these:

1. I will need to have any registered user of my site be an author. Also, as admin, I do not wish to moderate every entry by these authors. At the current time, I am noticing that WordPress does not publish a new post by an author till the admin clears it.

2. I am using the default them ( Kubrick), & find it very confusing about how to create a custom category page. On my site, i am creating custom categories, & need only certain modules displayed. I need something step-by-step that takes me through this process.

3. I will need users to have the ability to tag posts, as well as media associated with posts ( such as photos, videos). Are there simple add-ons I could use?

4. I want authors ( all registered users) to have the ability to create a new post from within the site, & not by going into the WordPress panel. How do I create a New Post page within my site?

I’ll have more but this is getting too long so I’ll stop here ?? Thanks!