Sigh how am i gonna explain you my joke while retaining the comedic effect...... Oh wait this is getting too meta
I'm really not the funny type and I don't really understand most of the jokes. So I can't help with that
Depends. If they don't get it because it references something they can watch/read, have them watch/read that, then tell the joke again. If they should be able to get it, but didn't get it, don't bother. If you're hellbent on explaining the joke, do an impression while explaining it. Whatever celebrity you think would be funny while explaining it. The joke still won't be funny, but you might get a laugh out of it.
3 month later were too short let them get it after 25 years just like the joke example below: "How did it happen?" the doctor asked the middle-aged farmhand as he set the man's broken leg. "Well, doc, 25 years ago ..." "Never mind the past. Tell me how you broke your leg this morning." "Like I was saying...25 years ago, when I first started working on the farm, that night, right after I'd gone to bed, the farmer's beautiful daughter came into my room. She asked me if there was anything I wanted. I said, "No, everything is fine." "Are you sure?" she asked. "I'm sure," I said. "Isn't there anything I can do for you?" she wanted to know. "I reckon not," I replied. "Excuse me," said the doctor, "What does this story have to do with your leg?" "Well, this morning," the farmhand explained, "when it dawned on me what she meant, I fell off the roof!"