To set the "Original Story Points" in Portfolio, you can either manually populate the column or you can Set Targets.
When you hover over an item in the Scope tab of a Plan, you will see a checkbox (this is the same checkbox you can use to exclude an item from the Plan). If you check that, another set of menus appears next toScopeat the top of the scope list. Click the one that says Set Targets.Set Original Story Points from Currentallows you to populate the Original Story Points column with what is currently in the Story Points column.
This also allows you to view the Target Schedule under the Schedulemenu next to the calculate button.
Story Points Column will populate from the hierarchy in JIRA plus the points listed in the Story Points Column.
On the Scope Detail (the list of issues), to the right of the # sign, there's a checkbox. If you check it, that will allow you to set targets (like the original story points).
There's not a way to "enable it" (unless you're running an old version of Portfolio for Jira). 2.18 is the latest. I don't remember which version added Target Schedules, but I believe it's been live since August 2017.
In the upper right hand corner, next to Calculate, you should be able to switch between Schedule, Capacity, and Target Schedule.
Select Target Schedule
Once you've done that, go ahead and select the issues again, and Set Targets should show up next to Exclude from Plan. I've included the link about Target Dates from the Cloud documentation below.
