Follow these step-by-step instructions to make your vegetable sushi rolls:

1. Rinse and Cook the Rice: Start by rinsing the sushi rice under cold water until the water runs clear. This helps remove excess starch, ensuring the rice is sticky but not mushy. Cook the rice with 1 ¼ cups of water according to the package directions.
2. Cool the Rice: Once the rice is cooked, let it cool for about 10 minutes. This cooling period allows the rice to firm up slightly, making it easier to handle.
3. Prepare the Nori Sheet: Place a nori sheet on a bamboo mat or a clean, flat surface.
4. Spread the Rice: Spread a thin layer of the cooled rice over the nori sheet, leaving a 1-inch border at the top. This border will help seal the roll.
5. Add the Vegetables: Arrange the avocado slices, cucumber, carrot, and bell pepper across the center of the rice. You can adjust the quantity of each vegetable to your liking.
6. Roll the Sushi: Starting from the bottom edge, roll the sushi tightly using the bamboo mat to help guide and shape the roll. Seal the edge with a little water to ensure it stays closed.
7. Slice and Serve: Slice the roll into bite-sized pieces using a sharp knife. Serve the sushi rolls with soy sauce or tamari for dipping.