A basic explanation of the rules for 'There is' and 'There are' as well as the past form

1. THERE IS/THERE ARE
We use there is/there are to explain that:
1. Something exists:
There is an apple on the table.
2. How many things there are:
There are five apples on the table.
3. Something is in a certain location:
There is a girl in the car.

2. The main subject follows the verb ‘is’ or ‘are’.
There is a pen near the computer.
There are some people at the bar.
‘There is’ is singular. ‘There are’ is plural.
There is a girl at the party.
There are some girls at the party.
We can contract there is = there’s (informal speech)
For negatives just add ‘not’
There is not a bottle in my bag.
There are not any bottles in my bag.
Contractions:
There is not = there isn’t OR there’s not
There are not = there aren’t
For questions we reverse the 2 words:
Is there an apple on the table? Yes, there is. OR No, there is not.
Are there three apples on the table? Yes, there are. OR No, there are
not.
Is there a boy in the car? Yes, there is. OR No, there isn’t.
Are there any girls in the car? Yes, there are OR No, there aren’t.

3. HERE, THERE (AND EVERYWHERE)
We use ‘here’ when something is near you or present in a specific
location (close):
The keys are here
Is my dad here? (the question asks if your dad is present in the same
location where you are)
We use ‘there’ or ‘over there’ to say something is not near you or
present in a specific place (far away):
The car is over there on the other side of the street
Is my mum there? (the question asks if your mum is present in the
location of the person you are speaking to – not where you are)