It's basically saying "solve for X where it fulfils all these equations":
X >= 500
X <= 1000
X % 2 = 1
X % 3 = 1
And asking you to write a program that determines all the possible numbers that fulfil the criteria.
So start by thinking about how you would do it manually:
1) Eliminate all even numbers between 500 and 1000 inclusive.
2) Eliminate all numbers that are divisible by three or which leave a remainder of tw0.
And then think about how you would code that: a loop that looks at all numbers in the range and checks if they match all criteria.
It's not difficult, but if you are having problems getting started at all, then this may help: How to Write Code to Solve a Problem, A Beginner's Guide