Not sure you want to describe the apartment as "cramped" within the Scene Heading; Use the Action section for that. Do we really need to know its YESTERDAY'S crossword puzzle as opposed to last week's or last year's? If vexed, show us, don't tell us. What does an insectoid voice sound like? Try being more descriptive if possible. Can we use a better word than 'friendly' to describe the voice?
INT. JIM'S APARTMENT / KITCHEN- DAY
JIM BARTHOLOMEW sits in his cramped kitchen, working through a newspaper crossword. He winces, taps his bottom lip with a pencil and looks up to the ceiling. A cheery, high pitched insectoid voice emanates out from Jim's body.
RANDALL (O.S)
Barrier
That's a start anyway... Also, if you want to get the free version of Celtx, you may download it here:
https://celtx.informer.com/versions/
2.9.7 is the last free version of Celtx