Displaying my content type in a block

God, I feel such a newbie, but I'm probably missing something obvious:

I'm working on a client website, the outside is a brochure site (inside is cleverer) but the client needs to be able to add project details on a regular basis for new potential clients to become involved in.

I can get all the basic stuff working, blog entries appear in the "latest blog entries" block, and so on.

But I need a block that display "projectdetails" where that is a content-type I've invented. Likewise I want a testimonials block with just "testimonials" in it. I just can't see how to make a given block display a specific type of entry.

I've searched every which way on this site but the keywords are so common I can't find what I need.

Help.

Please.

.