(Japanese) How to tell jokes in Japanese?

It depends on the part of speech of the word joke referred to by LZ.

1) If it's a noun joke, what the two upstairs said is OK. There are unnecessary conversations (じょぅだん), jokes, funny jokes, etc.

はとってもぃがでつもクラスメート.

He is good at telling jokes and often makes his classmates laugh.

2) If you are a verb, you can use ぁざぅ, ぁものにする and so on.

Used in sentences, such as

People laugh, laugh, laugh, laugh, laugh, laugh, laugh.

Don't laugh at others casually.