I got it mostly working.
The instructions at "Installation via Windows Package Manager" on Swift.org worked for me - not certain why they didn't work on my student's computer.
I did end up deleting the 5.10.1 toolchain and installing the 6.0 toolchain.
I tried setting the VSCode Setting for Swift > Debugger: use Debug Adapter from Toolchain. I then left Swift > Debugger: Path field empty and it seems to work but then I don't know if it's using CodeLLDB or the lldb-dap that comes with Swift 6. I then tried copying the path to the lldb-dap.exe into the field and VSCode says it cannot find lldp-dap debug adapter specified in the setting. I gave it the full path starting with "C:\Users" all the way to "6.0.0+Asserts\usr\bin\lldb-dap.exe" but it doesn't work like that or ending at \usr\bin without the filename (so just the directory path).
Does that Path need set and if so, what should it be?
I used "swift package init" and made a simple package with a test and I was able to get a Swift Package with the XCTestCase style testing to run (but not debug). If I right click and choose debug, it says "unable to find executable for ...\xctest.exe"
It couldn't "import Testing" to use the new swift-testing package, but I manually added it to the Package.swift file and I think I got it to find it and would work but this laptop only has 4GB of RAM so I gave up after a few minutes as the number of tasks needed kept growing and it didn't finish after a few minutes.
I was able to do use "swift package init --type executable" and use debugger in there and see the variable values if I set a breakpoint but the output never shows up anywhere (that seems to be a known issue with using Swift with VSCode at least on Windows).
I'd really like my students to be able to use the debugger in their tests so if anyone knows how to get that working, I'd appreciate it.
Thanks to everyone for their help. I'll give it another try with my student on his computer via Zoom to see if I can figure out what went wrong there.