Importing More Complex data for Classifier Learner

I need to use the Classification Learner tool/app to import more complex data than the examples online provides. (https://www.mathworks.com/help/stats/train-decision-trees-in-classification-learner-app.html).

All of the examples have a X 1xN Vectors of data which they import. I do not.

The data that I am importing looks like the data below. Note, Feature N and Feature M will be different sizes. I do not understand how to import data objects into the classification learner app where the data objects have different size fields (N and M below).

I tried creating a struct of data objects. But the classification learner does not understand structs?

Any helps would be appreciated, thanks.