Do you have pictures of the room that you can post?

What do the spaces ( all ) LOOK like now, and go back and put the windows in your drawing , with dimensions.......in all rooms.

You've handed us a mystery meat.

@Mae Day Organizing and Interior Design No pictures of the room. It's just drywall now and a blank canvas to work on

@JAN MOYER I have updated the image with dimensions and window width

The wall where we want to put the electric fireplace and TV is 120". Ceiling height is 9ft.

Thank you.

Even a dry walled empty room has that window. What we are asking, is what the heck does the house look like? Modern is a style , transitional is a style. You have no inspo pics of anything that might appeal to you, as if there was no Google!

We've no clue .......

I'd start with no less than a 72 - 84 inch fire ASSUME linear? and we must assume you are mounting on the wall? Go find it. You may not need a "design" at all. You can buy these ready to go, and use 2/3 of the wall. It won't need anything else

This is an easy one!

Depends on how big of a TV you want. If you want anything larger than 55" you need a linear fireplace. Pick the fireplace based on how big the TV is. Don't go smaller than the width of the TV if you can.

We installed a 100" Dimplex linear fireplace under our 85" TV. We built a surround for the fireplace so we didn't have to worry about heat affecting the TV.

You will need a dedicated circuit for many electric fireplaces if you want heat output.

Don't know if you want the fireplace to be see through or not. So here are some links for you to check out for linear electric fireplaces.

https://www.electricfireplacesdirect.com

https://www.woodlanddirect.com/see-through-electric-fireplace

Here is a 3D rendition with some suggestions for your consideration.