Seems a fairly large class.
Anything larger than 10 students per class, you really need to set down class rules, otherwise students can get the better of you and turn the class upside down.
Be fair and lay down the rules from the start.
I would recommend the following lesson plan (in order from start to end):
- Check previous lesson's homework. Get students to pass their homework to the student next to them for marking. That way, each student is marking another student's homework.
- Verbally test students on the previous lesson's content. Choose students at random and ask them questions. Use the sentences and grammar used in the previous lesson.
- Sing a song. (eg: ABC song, Head's Shoulder's Knees and Toes, etc.). To make it fun, you can even assign students to sing only a certain part of the song. The challenge then is to sing from start to end without 1 mistake. The student who makes a mistake, then would need to sit out, and the song would start again.
- Text work - Complete the next lesson in the student text.
- Assign and explain homework.
- Play a game. Hangman would be good for a class of your size. Hangman can be played as 1 large group. If using a board game or flashcards, then divide the class into 3 groups. Each group may be playing a seperate board game, and you can then rotate them in future lessons. This is providing you have ample floor space for students to spread out on.
I sure hope your school has set text books for students, otherwise it would be very difficult to teach them.
Good luck and I hope the above leads you in the right direction.