You will have to write short descriptions on each activity and they will have categories.
I really highly suggest making an excel document and separating your activities into the categories on the application, i.e. "volunteering", "paid work", "research," etc and having all the relevant information like contact numbers, hours, and dates so it's easily accessible come application time. The last thing you want to be doing is trying to recall so-and-so's name and how many hours you did. Keeping an updated log with all the pertinent info really streamlines the process. Best of luck.