how to declare variables

Answer 1

In the course, Basic Concepts module 10: Variables. Basically assign something a value.

like...
a=1

edit: Thomas's answer looks better :)

Answer 2

in python you can declare variables everywhere, just make sure you do so before using the variable
ex: a=5
print(a)
not: print(a)
a=1

Answer 3

In the beginning of the program declare the variables for eg,
x=10
print(x)

Answer 4

You don't have to declare it separately. You need to initialise it anywhere in the code before you print the variable.