IUPAC naming rules for coordination compounds:

1. Ligands are named first in alphabetical order.

• $N{H}_3$ is called ammine.
• $C{l}^{-}$ is called chlorido.
• Alphabetical sequence: ammine before chlorido.

2. Numerical prefixes ($di,tri,$ etc.) are used for multiple ligands (but ignored for alphabetizing).

• Two $N{H}_3\to$ diammine; Two $C{l}^{-}\to$ dichlorido.

3. Central metal follows ligands. Since the complex is neutral, Platinum is used.
4. Oxidation state is in Roman numerals: $x+2(0)+2(-1)=0⟹x=+2$.

• Result: Diamminedichloridoplatinum(II).