Answers and Explanations:
There are several different ways you could write this. Depending on what time frame you'd like this statement to take place, depends on how the statement will be formed and said.
Past-tense: Tome stayed home on Monday.
This is saying that Tom had stayed home on Monday, implying that this was an event that happened in the past.
Present-tense: Tom will stay at home today.
Because the word today is placed in this sentence, it is stating that this event had happened today specifically.
Future-tense: Tom will stay at home on Monday.
Because of the way that this statement is said, it is saying that this will happen in the future, ahead of time on this certain day.
I hope this helps.