What is the best way to input actions using an Excel spreadsheet?

No, there is currently no way to do this. May I know what's your usecase for using Playlyfe along with an excel sheet?

as an input form for an action.

I think what he meant is what is the overall use case for this ? Are you trying to gamify processes for a sales team(or something like that) ?

the use case is a warehouse where workers are performing work, say order picking in lines per hour, the action. Their productivity is recorded on an excel spreadsheet which can be exported in a csv file. The goal is to award points and badges for improved productivity.