Every survey collects data and stores it in a structure called an Instance.
The Instance has a Node for every piece of data. For example, if you have a question "What is your name?" the question is assigned a Node in the Instance, the name is arbitrary, so it can be "name" or it can be auto-named by the KoBo Form Designer. The Form Designer assigns names sequentially, A01, A02, A03...
However you name the nodes assigned to each question, it is important to understand the role of node names in the final output of a survey form. After data collection, KoBoSync will combine all the surveys into a Comma Separated Value (CSV) file. The node names will provide the heading names for the data. In a spreadsheet or database, the node names will label each column of data.