You're going to need a computer/tablet to display the pictures on and several whiteboards, markers, and erasers for the student teams you'll make.
If your students don't know Pictionary, start by drawing Anapanman (even if, like me, you're terrible at drawing, he's pretty easy) and ask the class to guess who you're drawing. They'll guess quickly. I've drawn Anapanman many times and kids always recongnize him in no time. Then write, "This is Anapanman." You'll likely need your JTE's help to explain that since Anpanman is close to you, you would say "This is...", but since he is away from the students, they should say, "That is..." Japanese linguistics mesh with this idea pretty well, so the kids should get it without too much trouble..
Now put students into groups and give a whiteboard, maker, and eraser to each. Explain that you'll show one person from each group a picture. You can have them draw on the blackboard, or on the whiteboard at their group. Once the stuents have guessed who the character is, the student who drew should say, "This is... He/she is..." and write it on the whiteboard. The other students shouls respond with, "That is..."
Next it's time to add a "He/she is..." to the whiteboard. I recommend letting students use their books to help choose adjectives. For example, pg. 145 in "Here We Go! 1" has such a list. All the students should try and help make the sentence, but the studen who drew should write this part too. Once everyone is done, the whiteboard is passed to the student to the right of the one who did the drawing. Repeat so that every student gets a turn.
That's all there is to it. Good luck.