Summarize this article:

Place the rhubarb stalks on a flat surface, like a cutting board. Trim off the top of the stalks where the leaves are. Make sure you remove all the leaves, as these are poisonous. Trim off the bottom inch (2.5 cm) of the stalks as well, where the rhubarb was touching the ground. Rinse the rhubarb under cool, running water. Use your fingers or a clean cloth to scrub away any dirt on the fruit. Rhubarb is fairly hard, so you can also use a vegetable brush to scrub it clean if you like. Lay the stalks on a clean towel and roll each stalk around to dry it. You can also dry the rhubarb in a salad spinner if you have one. Transfer the rhubarb stalks back to the cutting board. Chop each stalk into quarter- to half-inch pieces (6 to 13 mm). Smaller pieces are ideal for jams, pie fillings, and baked goods. Larger pieces are better for eating plain or making chunkier compotes. If you have specific plans for the rhubarb, consult the individual recipes to determine the right length for the pieces.

Summary:
Trim off the leaves and tips. Wash and dry the rhubarb. Chop the stalks into bite sized pieces.