Hey, thanks! No silly questions don't worry.
If I'm understanding correctly, you want to print these for your tabletop games right? I think that's awesome!
As for what app or program to use, do you mean to set them up for printing or to use the assets to make scenes for your games? If the latter, then I'm not sure what the best answer would be.
For making the mockups shown here (and the assets) I used Aseprite, which is a pixelart program with a cost of 20 USD. It has a tileset mode that is really awesome for making tiles and mockups really, but I think unless you're going to take up pixelarting then it's probably not the most accesible solution to your question.
Another program you might want to try (and one I've used for more than a decade myself) is GIMP. It's free but it's not really set up for tiling or pixelart from the get go, it'll be a bit tedious if I'm honest (compared to Aseprite or other programs dedicated to tiling).
Anyway, apologies if I didn't get your question right! Cheers