This can be a plastic cutting board, a piece of scrap wood, or any other sturdy, flat surface that can be spared for a while. Avoid cardboard, as it will likely be too flimsy to support your project. If you’re working with scrap material, consider decorating the base to look like a flat landscape. You may want to paint it, cover it with moss, apply green felt to indicate grass, attach miniature trees, etc. Since you will build the volcano around the bottle, be sure to place it in the center of the base. How you attach it will depend on what your base is. If it’s a kitchen cutting board, place a lump of clay or Play-Doh on the board and lightly crush the bottle into it for a loose hold. If you’re using scrap wood, use a plastic/wood adhesive.  A caramel-colored soda will probably look the most like lava when your volcano erupts, so avoid clear drinks. Both diet and regular soda work for this experiment, but diet soda erupts higher. If gluing the bottle, let the bottle reach room temperature. A cold, sweating soda bottle will never glue properly. Avoid using hot glue, which might melt the bottle and make a mess. If you’re doing a vinegar and baking soda volcano, you will attach an empty bottle to the board. For a textured look, shape some chicken wire into a lumpy, mountainous cone around the bottle. Cover the chicken wire with papier-mâché. An alternative to paper-mâché is to sculpt some clay around the bottle. For a more solid look, shape green, gray, or brown play-dough or clay around the bottle. Avoid covering the cap of the bottle or you won’t be able to activate the volcano. Ensure you have access to the opening so you can add Mentos or baking soda for the eruption! After you have let the paper-mâché dry, paint it with acrylic paint (which will also help seal out moisture). Use shades of brown and orange around the top and add some green to look like grass. You may even want to press pebbles, dirt, and moss into the surface to give it a more natural appearance.

TL;DR in Indonesian:
Buatlah alas untuk gunung berapi. Letakkan satu botol soda berukuran dua liter yang belum dibuka di bagian alas. Buatlah gunung berapi di sekitar botol. Cat gunung berapi.