another newbie question: running multiple tests in a project

I have a project suite with a single project (so far).  Inside that project, there are multiple test items (keyword tests).  How do I run them sequentially?  No matter what I do, I can't seem to run more than one at a time. 



I know there must be a way to do it, otherwise I'm not sure it makes any sense to be able to organize them into projects.



Thanks,

Richard