These are all very different particles. Ka - usually used at the end of a sentence to indicate that it's a question. It is also used between nouns to mean "or". Wo - (pronounced "oh") this marks the object of the sentence, so whatever is being acted upon. If you are going to eat steak, it would go something like "sute-ki wo tabemasu". Wa - (sometimes written "ha" because that's the hiragana that's used) this marks the topic of the sentence. As you learn, you'll realize it's hard to tell the particles wa and ga apart. Just remember, wa goes on whatever noun answers the question "what are you talking about?". We don't really have a sentence part just for topics in English, we normally just get it out of context, which is why it's so hard for us to wrap our heads around the fact that they have a part for topic and a part for subject (ga). Also, Japanese drops words like the subject, topic, and things quite often. Also, they often drop just the particles, so it wouldn't be weird to hear something like "sute-ki taberu". It happens more often in casual speech.