Step1:
Execute this rule with your report ID.
= getPortalReportDatasubset(
  reportId: 4063, (use your report ID)
  pagingInfo: a!pagingInfo(
    startIndex: 1,
    batchSize: 0
  )
)
======================================================================================================================================================
Output:  (report structure)
[startIndex=1, batchSize=0, sort=, totalCount=0, data=, identifiers=, report=[name=All Process Models, description=A list of all process models.],
columns=[label=Name, field=0, alignment=LEFT]; [label=Creator, field=2, alignment=LEFT]; 
[label=Created, field=3, alignment=LEFT]; [label=PMId, field=4, alignment=RIGHT]; [label=Current version, field=5, alignment=LEFT]]
======================================================================================================================================================

Step2: Determine Field IDs what you wanted to filter data (In my example: Field 0,1 are Process name and created user)

step3: 
Example: 
= getPortalReportDatasubset(
  reportId: 4063,
  pagingInfo: a!pagingInfo(
    startIndex: 1,
    batchSize: - 1
  ),
  contextIds: {},
  filters: {  /* here Field IDs are constant values for a report, Just run getportalreport datasubset function and find the field Ids' */
    {
      field: "0",
      operator: "LIKE",
      value: "* Update *"
    },
	{ field: "2", operator: "EQUAL", value: "radhaa"}
  }
)

You can see the attached pdf document for mor operators and related functionality

======================================================================================================================================================
Output: 
[startIndex=1, batchSize=-1, sort=, totalCount=2, data=
[cells=[value=TMs Update Process Constants, drilldown=26]; [value=TMS Update Training Config, drilldown=5]];
[cells=[value=radhaa, drilldown=]; [value=radhaa, drilldown=]]; 
[cells=[value=12/22/2014 4:53 PM GMT+05:30, drilldown=]; [value=12/22/2014 4:52 PM GMT+05:30, drilldown=]]; 
[cells=[value=26, drilldown=]; [value=5, drilldown=]]; 
[cells=[value=21.0, drilldown=]; [value=1.0, drilldown=]],
identifiers=26; 5, report=[name=All Process Models, description=A list of all process models.],
columns=[label=Name, field=0, alignment=LEFT]; [label=Creator, field=2, alignment=LEFT];
[label=Created, field=3, alignment=LEFT]; [label=PMId, field=4, alignment=RIGHT]; [label=Current version, field=5, alignment=LEFT]]
======================================================================================================================================================

Step4:
If you want to retrieve Specific columns then use column array values not the field IDs.
Example:
load(
  local!datasubset: getPortalReportDatasubset(
    reportId: 4063,
    pagingInfo: a!pagingInfo(
      startIndex: 1,
      batchSize: - 1
    ),
    contextIds: {},
    filters: {
      /* here Field IDs are constant values for a report, Just run getportalreport datasubset function and find the field Ids' */{
        field: "0",
        operator: "LIKE",
        value: "* Update *"
      },
      {
        field: "2",
        operator: "EQUAL",
        value: "radhaa"
      }
    }
  ),
  {
    ProcssName: local!datasubset.data[1].cells.value,
    CreatedBy: local!datasubset.data[2].cells.value,
    Creator: local!datasubset.data[3].cells.value
  }
)