Here's how to run the program. I had difficulty running the software and understanding the build process. The installation assumes a lot of knowledge about the command line. I eventually managed to get through it, so here's a breakdown of how to run the software (specifically for windows, but should make sense on other devices):
First you need to install UXN. UXN is like a specially built virtual computer. The ROM software runs on this.
Do the install by following this tutorial - I'll help you through the difficult parts here. If you do not have it installed already (which the tutorial presumes), install git bash from here https://git-scm.com/downloads. Follow the install wizard - the recommended installation information should be fine. Specifically you want to add git to bash (the command line interface we'll be using shortly).
For Windows, which was my operating system, I then had to download MSYS2. When it's installed, search in your start menu for 'MSYS2'. You want to run the 64 bit version. When a black screen comes up, you'll need to type out the commands listed in the tutorial. After each line that you type out, press enter. Each line is a single command. When it asks whether you want to install you must type a lowercase 'y', not 'Y'. When you've finished the commands you should see a synth window appear. This is UXN. You can close this after you've played around with it. The command line window will not accept new commands while UXN is open.
Run the ROM
Now you have UXN installed, you'll want to download the .rom file from itch.io and put it into the UXN directory. UXN has been installed at C:/msys64/home/[username]/uxn. You can go to this folder in explorer and save your noodle.rom here.
Now open MSYS2 from the start menu again. By default it opens at C:/msys64/home/[username]. If you type 'ls' (the "list" command) you can see a list of files and folders within this directory. You should see 'uxn'. If you type 'cd uxn' it'll allow you to change directory ("cd") to the uxn directory. This will take us to C:/msys64/home/[username]/uxn.
From here you can run your noodle.rom. Type 'bin/uxnemu noodle.rom'. This means "run the program 'bin/uxnemu' with the file 'noodle.rom'".
You may see other documentation online which ask you to compile roms using the assembler. To do so you can follow the same pattern as above but target the program 'bin/uxnasm'.
When you want to open your software again in the future, you can open MSYS2 and type in 'uxn/bin/uxnemu uxn/noodle.rom' without needing to use the cd command. This command is slightly longer but it involves fewer steps.
You can also try some of the demo programs that come with UXN. Try 'bin/uxnasm projects/examples/demos/[whatever].tal [whatever].rom', then launch it with 'bin/uxnemu [whatever].rom'.
I hope this was helpful. Apologies if I'm stepping on anyone's toes by making this tutorial.