If you have the Probate Plus support pack installed correctly (see here for help) then you can build a bundle of forms within the suite of IHT400 forms offered by Laserforms.
With Laserforms already open outside of Probate Plus, just go to 'Forms...Build a form bundle' and choose which bundle you would like to use. The standard installation offers you a bundle from the IHT400 or IHT400+ suites.
A screen will appear in which you can untick any schedules you may not wish to include for your particular estate.
When the form bundle has opened, go to "Forms...Fill in active Laserform"