To replace existing content:
Create a new folder named pak01_dir and put your content structure in there. (eg. pak01_dir\materials, pak01_dir\models.) Drag this folder onto portal2\bin\vpk.exe. Copy your new pak01_dir.vpk into the mod template folder (portal2_test by default.)

To launch the mod:
Either create a shortcut or batch file that launches portal2.exe -game portal2_test -steam (you'll need to change portal2_test when you rename the mod).
I've also made a batch file that allows you to launch a mod folder by dragging it onto the batch file for your testing convenience.

Be aware the mod uses independent settings from Portal 2 (bindings, screen resolution, etc.)

If you get a crash:
Delete modelsounds.cache and replace bin and cfg with the ones from your portal2 folder.

yohoat9 wrote:
Can you get a little more detailed on how to create the batch file? Also when I try to launch it crashes, is that normal?

I provided an example batch file. And take a screenshot of how Portal 2 looks when it crashes and I'll look into it.

Omnicoder wrote:
yohoat9 wrote:

Can you get a little more detailed on how to create the batch file? Also when I try to launch it crashes, is that normal?

I provided an example batch file. And take a screenshot of how Portal 2 looks when it crashes and I'll look into it.

I would take a screenshot, but it doesn't really show anything like an error or anything. It just closes right after the valve and source logos.

yohoat9 wrote:
Omnicoder wrote:

yohoat9 wrote:

Can you get a little more detailed on how to create the batch file? Also when I try to launch it crashes, is that normal?

I provided an example batch file. And take a screenshot of how Portal 2 looks when it crashes and I'll look into it.

I would take a screenshot, but it doesn't really show anything like an error or anything. It just closes right after the valve and source logos.

See the bottom of my first post for a fix that has worked for most people.