Step 5. Define fragments

Define the PtCl₄^2- and H₂ fragments:

Select the Pt and Cl atoms
Use the 'New Fragment...' command to define this as the PtCl4 fragment
Select the two H atoms
Use the 'New Fragment...' command to make this into an H2 fragment

Now the fragments are defined. Next, use the 'Fragment Analysis' preset to set up the fragment analysis calculation:

Select the 'Fragment Analysis' preset
Open the 'Task: FragmentAnalysis' panel
Change the charge of the PtCl4 fragment to -2

Save

The other changes (the overall molecule charge, and the scalar ZORA option) have already been set previously. The Fragment Analysis preset does not change these.

When you click on the Open... button next to the PtCl4 fragment, you can inspect the PtCl4 fragment setup:

Click on the Open... button next to the PtCl4 fragment in
  the 'Task: FragmentAnalysis' panel
Check the charge of the fragment in the newly opened ADFinput (shoud be -2)
Close the PtCl4 fragment ADFinput window

For more complex calculations, you could make additional changes to your fragment runs. However, normally the set up as created by ADFinput should be fine.