Keep each lesson simple and do not cover too much at a time. Use a lot of exaggerated actions and act out instructions, for example, you can sit down and say "sit down" at the same time while pushing downwards with your palms towards the floor.
Children pick up instructions like "close your eyes, open your eyes, stand up, sit down, make a circle" very quickly. Make sure to play simple, fun listening games in the beginning so that children can play even if they don't understand the instructions.
A few simple ideas:
1. Place 5 animal flashcards on the table or the mat if you prefer sitting on the floor
2. Point to each flashcard and say the animal out loud
3. Say the name of a child and say "show me the lion". The child will only understand the word lion, if you have drilled the flashcards enough, but if you make an exaggerated "where is" gesture he will point it out. If not, do it yourself and then ask another child to show you another animal and so on until everyone has had a turn
4. Stand up and say "stand up" while pushing your palms upwards
5. Show a flashcard and make the sound of the animal and walk around the room moving the way the animal would. If you have chosen a monkey card then jump around the room while making the "ooh, ah, ah" sound monkeys make. Children will join in.
6. Sit down again and put the flashcards upside down and ask "where is the lion?" to one child. When he turns over a card and finds an animal that is not a lion, say loudly "monkey" and show him the card for him to say monkey. Do this until every child has had a turn at looking for the card you have told them to look for.
These are just ideas but they show you don't really need to be able to speak a child's language to play games with him. Give your students a reason to talk and play simple games where children listen to what you are saying. Read this article
on encouraging a silent class to talk and apply the same ideas to your class.
Lastly, do not be too stressed out, they're only children! Have some fun with them and it'll be fine.