Setting data for Point parameter

in the Remarks section (point parameter > help > remark) it is said that:

If you reference points as being on a curve or edge, then you can specify how the relationship is constructed. The point can be defined both as a certain percentage along the curve span, or as a certain distance from the start or end.

I tried fraction and percentage (in Ratio method) and length (in FromStart method) but the command line does not accept any of them

Do I misunderstand the remark or what?

It’s probably a method forgotten even by devs.
I’ve almost never seen it being used here.

You can’t give numerical input, only click on curve and that’s it.
But then you can right click in your point parameter, go to “Manage point collection” and manually edit the ratio parameter or distance from start or end.
BUT… it’s wrong!
The “ratio” option, seems to be a 0-1 reparametrized value of the parameter on the curve, not actually a length ratio. Just avoid it completely.
And the from-start or from-end options are just tricky to use, you lose the parametrization feature in your code, making the edit of that length really not practical.

I’d strongly advise you to reference a curve instead, and use Evaluate Length with normalized = true/false depending on your need. (And flip curve if you need length from end).