Import several layers of terms

I have been testing the schema and test file to grasp how I can upload some thousands terms I have in excel divided in 5 different levels. My first step was to import the scema and start mapping the scema to an empty excel file. But this is where I get lost. How can I map terms from excel that are build in several layers - a hierachy. Example of how I have it in Excel:

Term x1
Term x12
Term x121
Term x13
Term x14
Term x141
Term x142
Term x2
Term x3
...