Read/Write/Edit SharePoint 2013 Data inside Visual Basic Windows Application

Does anybody have any experience with creating a windows application with a SharePoint 2013 data source? I have a couple of apps that read/download library files and read/write lists. This all works very well. But, when it comes to creating a new record, I’m having a bit of a struggle trying to add a person to the “Assigned To” field in a Task list. Also, I’m not finding a way to update an existing custom list. I’m trying to check a checkbox field. I’ve used the Data Source Wizard to connect to the SharePoint 2013 sites. So I can accomplish what I need, except for these 2 things. So any guidance will be very appreciated.