1. Clean the aquarium thoroughly, fill it with water, and let it stand for two days to check for leaks. After confirming no leaks, wipe it clean. Pay attention to the placement of the aquarium, avoiding areas with significant temperature fluctuations, noise, or concentrations of electrical appliances. Before adding the substrate, rinse it with seawater. The substrate should be approximately 2-3 centimeters deep in the aquarium.

2. Prepare artificial seawater, and be sure to test the specific gravity, which should be around 1.022. Slowly pour the prepared seawater along the substrate, taking care not to disturb the substrate excessively.

3. Set up a waterfall filter, preferably a larger one for better filtration.

4. Since you will be keeping marine fish and sea anemones, you will need a heater. Position it to extend horizontally across the bottom of the tank and attach it in a visible location. Also, set up a temperature gauge. In the summer, a small fan can be used to cool the nano-tank.

5. To speed up the maturation of the tank, add marine nitrifying bacteria to the water.

6. Check the operation of all equipment, then pour some seawater into the filter. Test the seawater for various parameters approximately once a week. It is also recommended to test for ammonia and nitrite levels.

7. After a period of water conditioning and once the water quality meets the standards, you can introduce marine life, including some sea anemones and corals. Pay attention to controlling the number of organisms and choose hardy species. Be mindful of temperature changes, especially in smaller tanks.

8. Finally, set up the lighting. For marine aquariums, choose a combination of blue and white lights that look more attractive. The lighting should be on for 8 hours, and it's best to have a lid to prevent water splashes.

Additionally, please note that after adding food, change a bit of the water that contains debris to maintain water quality and quantity. It is essential to establish a good environment by changing one-third of the water weekly and regularly checking the temperature and water quality.