Peace be upon you. It is sufficient to immerse the entire body in water with the intention of performing a complete ghusl in the required order, as this will ensure that water reaches all parts of the body. According to Ayatollah Sistani, it is enough to wash the part that needs to be cleansed with the intention of performing ghusl, and this will ensure that water reaches all parts of that section. It is recommended to wash the right side before the left side. For further details, you may refer to the sources provided.