Help wanted

I am new to this whole blog thing and am still learning the ropes. Often it takes me two or three tries before I get a post to look the way I want it to. I think I have mastered most of the important aspects of the world of blogging, except for one: How to link other blogs in my posts. I see this all the time in my friends' blogs. They will reference something and there is a link to it. For the life of me, I cannot figure out how to do this! My friend Caranine is an extremely adept blogger and has references and links to her own previous blogs right in her text. How she does this, I do not know! But if anyone reading this knows how to accomplish this task that has eluded me, please enlighten me!