Last time, we learned about the particle は. There are more particles, and knowing them will help you form sentences. Let's take a look at a few more particles, namely で (de), に (ni), へ (he), and を (wo).
The particle で tells us where an action takes place. It is placed after the location and before the verb.
こうえんでテニスをしました。 (kouen de TENISU wo shimashita)
I played tennis at the park.
The particle に has a lot of meanings, and will most likely be a particle that will confuse you at times. For now though, let's just take a look at two of its meaning: movement consisting of a goal, and the time something happens (it is placed after a time reference).
わたしはこうえんにいきます。 (watashi wa kouen ni ikimasu)
I will go to the park.
ろくじにしゅくだいをします。 (roku ji ni shukudai wo shimasu)
I will do homework at 6 o'clock.
*じ = hour
The particle へ, pronounced "e" (like え), is also used for movement. It's basically another version of に, but strictly only the meaning of having a goal for movement. You can use に and へ interchangeably, but again, only in the sense of movement towards something.
The particle を, pronounced "o" (like お), indicates objects/nouns that are affected by an action/verb. It is placed after the object and before the action in a sentence.
きょう、テニスをします。 (kyou, TENISU wo shimasu)
Today, I will play tennis.
*します = to do, so literally, the sentence means "Today, I will do tennis."
As you can see, を takes place after テニス, meaning that テニス is the noun being affected by the verb, します.
With more practice, understanding of particles will come naturally. The more you see them, the easier of a time you'll have. Also, many verbs are specific with which particles they use. That means you'll have to memorize which correct particle to use or else your sentence won't be correct.