Hey there! Congrats on taking the opportunity to teach the younglings! I really enjoy teaching the younger students the most.
As for your questions...
Definitely get some flashcards printed and ready. Students respond very well to them and they can be used for a LOT of different games. You can find some great games at Dave's ESL Cafe
. You can find some flashcards at the link in my sig or at Free Printables for Teachers | flashcards, printable games, worksheets templates, phonics materials, ESL printables, conversational activities
TPR is also a must with younger students. Think of TPR like a massive game of charades always taking place in your class...only, when you do the actions, you say what you are doing (unlike charades). When you are talking about animals, do an action for that animal (like having your arms or hands becoming an elephant when you say the word elephant). Having the students do the same actions are also very entertaining for them and it helps them learn better.
As for discipline...establish your rules in the beginning of class and make them easy to understand. In my lessons I have converted all my rules into four simple ones. On the board I draw eyes, ears, a mouth, and a heart. These pictures mean look at me, listen to me, don't talk, and be good and happy.
(The don't talk part is really just not to talk when I'm talking or others are talking).
Another thing I do with my young classes is to write my students' names on the board. Every time they do something well I will give them a point (maybe a star...should be something that can be drawn quickly). If a student can accumulate a predetermined amount of points in class he or she can get a treat (maybe a small candy). If a student misbehaves, I will erase a point....making it harder for them to get the treat.
Also, songs and games should be used often. Young kids have a shorter attention span than older ones and switching up activities every so often will keep them interested in your lessons.
If you have any other questions or need any more help just let me know.
You can also check out my blog at Keep Up With Richard
I focus on teaching younger students mostly so there should be some things of interest to you there (you can check this link for a TPR post Keep Up With Richard » Blog Archive » TPR (Total Physical Response) in the classroom