Where can I download it? I only see links for the 64 bit version.
Just to be clear: The legacy-compat branch for a version of Avidemux which would be able to run on Windows XP hasn't been updated since Juli 2020 and I have currently neither time nor energy to backport over 500 changes to revive it. The maintainer of the project still has a functional build node, so it is theoretically possible.
A 32-bit build from the git master (or from 2.7.8, but who would want it if git master is better?) should be absolutely possible for everyone who is ready to invest a couple of hours into setting up a Linux system, see cross-compiling.txt (https://github.com/mean00/avidemux2/blob/master/cross-compiling.txt) and the script mxe/mxe-setup.sh (https://github.com/mean00/avidemux2/blob/master/mxe/mxe-setup.sh). It hasn't been tested a while (but it worked back then, in February 2021), bug reports welcome.
TLDR: There are no binaries to download. It should be very easy to cook your own.
I'm on Windows 10, using 32 bit version 2.7.6. I'm just looking for the new version because there is no link to download.
https://sourceforge.net/projects/avidemux/files/avidemux/2.7.8/
You need a Linux system (a VM with a lot of hard disk space and memory should suffice) to build your own. There are no official 32-bit builds.
(However, you will need 64-bit capable hardware to build a 32-bit Avidemux for Windows).
32-bit builds up to the 2.7.6 release you run targeted specifically WinXP, they used an ancient FFmpeg version for this purpose and were a pain to maintain. The current git should be fully functional (just not the VapourSynth support, but oh well...) when compiled for 32-bit, there are simply no official builds as the target audience (users of 32-bit Windows 7 - 10 installations) is pretty small.