These are the steps @Don von gave a little more detailed:

Base Model Acquisition: The process begins with acquiring a base model from a website like 3DExport. This base model serves as the starting point for creating the trigger.

Model Editing: The acquired model is then opened in 3DSMax or Blender, which are popular 3D modeling software. Here, the model is edited to suit the requirements of IMVU's 3D engine.

Polygon Reduction and Weighting: The model's quality is reduced by decreasing the number of polygons to ensure compatibility with IMVU's 3D engine. Additionally, the model is weighted to match one of IMVU's avatars, which likely involves adjusting the model's rigging to fit the avatar's skeleton for proper movement.

Texturing: Once the model is prepared, the texture mapping process begins. This involves applying textures, including the design for the "dick" in this case, onto the model's surface to give it a realistic appearance.

Exporting for IMVU: After texturing is complete, the model is exported in a format suitable for IMVU's create mode. This likely involves specific file formats or requirements set by IMVU.

Texture Design: With the model loaded into IMVU's create mode, the texture design process can begin. This step involves designing the appearance of the "dick" within the IMVU environment.

Creating Morph States: In order to animate the trigger, various morph states are created in the 3D modeling program. These states represent different configurations of the trigger, such as limp, hard straight, hard pointing up, and hard fat.

XML Coding: The morph states are then coded into XML files known as xpf morph files. This coding allows for the trigger to change between the different states and enables animation within IMVU.

In summary, this process involves acquiring a base model, editing and preparing it for IMVU, applying textures, designing the appearance within IMVU, creating morph states for animation, and coding these states into XML files for functionality within the platform.

I have not used studio, so I would not know. Personally, I use Blender and IMVU Classic desktop.

the most i've made is a shirt with a album logo on it :/

There's a whole lotta work needed for those afaik. I'd say the hardest part is learning to work with Blender, which is an absolute pain unless you watch a whole bunch of tutorials first just to get ahold of the basics. Even then, you're still gonna have to spend hours creating and editing models, making sure they function the way they're supposed to or whether or not they look the way they're supposed to. Ntm, having a decent device is optimal if you want it to turn out right. Though if you're really keen on creating, you just gotta make sure you have the grit to keep going. The rest comes with a whole bunch of trial and errors. I'd suggest you start with the basics (creating models & making models function separately) before combining both and applying that to triggers. That way, it won't be as overwhelming.

Hi bro...
I was searching... and couldn't find any good tutorial for IMVU Studio Toolkit. It would be helpful if you could recommend how to use Blender and the IMVU Classic desktop.
It would be a great help, or if someone gives a course on how to learn.

For 3D modeling tutorials, visit our partner, Dallo's Education Creations Syndicate: https://discord.gg/nQef9hU

Thanks brother...
At least with this I will be practicing and learning. I hope I can do the rest of the steps. xd

might learn from this and make some competition for you guys lol

Rising water lifts all ships.