Using tell requires one of the following grammar constructions:
1. tell somebody something
2. tell something to somebody
For example:
He told everybody he saw the news.
He told the news to everybody.
Explainsomething (to somebody)
For example:
You should explain the rules of the game to your friends.
You cannot say explain me because in this case, you must use the above mentioned form to somebody.
So, instead of explain me, you can say, for example, Explain to me what to do in such situations