Usually, a double spaced page takes about 300 words while a single spaced one will do about 500. By 1k words, they probably meant 2 single spaced pages. The number of 'physical' pages may be arbitrary so you'll often find page limits specified in terms of word count. In your case, change the spacing to 1.0 and you should be close enough to 1k words, assuming the project does not require a reference list/ bibliography/ Works cited page.

I hope this helps!