First you can try searching this forum as many of your issues have been answered in other posts. Next, for Magento related issue like how to get things to appear, check the Magento forums.
You can look at your layout files (homepage, 2column-right, etc.) to move the recently view products to where you want it. Twitter is hardcoded into the homepage.phtml file, so you can comment that out there. There are tutorials here on HT on how to add the slider to your site.
Note that Magento is a real beast, and from your post I gather that you are really new to this platform. i suggest you go through all tutorials on the Magento site and read through the forums for more answers. This forum is reserved for template related issues really.
I hope I pointed you in the right direction, but beware that if you are asking these questions now, you will probably get very frustrated with Magento if you don't study!