What is the difference between a mood and a tense? Why is the subjunctive a mood when it has its own verb forms? Why isn't it just another tense?
The mood shows if the information is true - in indicative mood, an assumption - in subjunctive mood or is it an order or a command - in imperative mood.
On the other hand if we talk about a sentence in indicative mood; we can use different tenses to show how are the events described placed in time.
Shut the door ! - it is a command - a sentence in imperative mood we cannot say when the thing happens - there is no tense in this sentence.
I would buy a new house if I won on a lottery - it is a sentence in subjunctive mood; we only show suggestions or assumptions. The situation described is possible but has not yet happened.
I get a lot of books as presents - here we talk about a repeating situation, so we use Present Simple tense.