If you want to make changes to the blender model, download the blender file and open in Blender (note: this software is free and is extremely useful!). Make changes to the blender as needed and export as an STL for 3D printing. If you keep the cutouts, make sure you only select the actual body and arms -- leaving out the parts used for boolean modifier cutouts -- and check the "only export selection" box when you export as an STL. Otherwise, download the body, left arm, and right arm STL files.

You can use a software such as Orca slicer or any other 3D printing software. We recommend using tree supports and trying to avoid placing them on the ears since it will make the print come out a bit rougher. It doesn't really matter what filament color you print the rat in, since you can paint over most 3D print filaments. However, gray will show up better on some filament colors than others.

Paint the body a light/neutral gray and paint the inside of the ears, hands, and feet pink.

You can find countless breadboard and arduino tutorials online. We recommend first making sure the basic electronics work before doing any soldering or installing any of the electronics in the rat.

This should cause the LEDs to light up and the servos to rotate within a small-ish angle range. You may have to change the ports depending on how you configure your breadboard.

Typically, when you buy small servo motors, they come with small plastic attachments like the ones in this link: https://www.pishop.us/product/sg90-180-degrees-9g-micro-servo-motor-tower-pro

This allows for the LEDs and servo motors to be farther away from the breadboard. We couldn't find long pieces of insulated wire, so we just taped together a bunch of breadboard jumper wires and then cut the ends of one of them and soldered them to the LEDs.

Place the servo motors with the moving arms inside the rat where it will be glued and see if the angle range in the arduino software is calibrated correctly (it probably won't be for a new user). Adjust the angles so the arms are moving in the correct angle range.

Feed the LEDs through the back of the rat's head through the eye holes. You shouldn't need to hot glue the LEDs in. Hot glue the two servo motors together first and then hot glue them to the rat after.