Hi Shyvia,
First of all, I warn you that passing structures as input variables, because in terms of performance has a similar impact to the use of session variables, they are discouraged, as their use will help to fill the viewstate. , which makes screen loading slower. I think the best method will be the same as already mentioned, by JSON serialization, where on the first screen you serialize the structure to JSON, you pass variables as text to the second screen, and on OnInitialize you do the deserilization to JSON.
Check this exame: https://www.outsystems.com/learn/lesson/1881/handling-json-data/
If you need more help, let me know!?
Regards,
Nuno Verdasca