1. Click "New Post" in the top left hand bar when you're logged into Blogger and on welovemediacrit.
2. You'll see a screen that looks like this:
You can type your entry into the main box. Click "publish post" when you're done, or click "Preview" (above the text box) to see if everything looks okay. You can always edit your post after you post it!
TIP: Write out your entry in a word processing program first so that if your browser snafus/crashes/whatever, you won't lose your post.
3. To post images, click the image picture on the toolbar to the right of the "Link" button. You can either upload your image to the blog directly, or link to an image you found somewhere else on the web. To do the latter, you'll need to know the URL of that image. Here's a mini tutorial on how to find out the URL of an image, if you don't know how.
4. To post YouTube/Hulu/whatever videos, you can paste the HTML directly. On YouTube, the HTML can be found in the "About this Video" box while you're watching the video (help from Google). In Hulu, there's a "copy embed code" button under the Main tab below the video. Every other video site should have a way to embed videos; read their Help, Support, or FAQ sections if you can't figure it out.
5. If you want to add audio/video/images but absolutely can't figure out how, just create a link to the page using the link button above, so people can click through themselves.
Finally, Blogger has a big Help section. Try there if you're still having trouble.