Row two is your start row. Change the values to whatever your current stats are, and change the date in cell A2 to today. Then, tomorrow and every day thereafter, enter the quantity of reps you did, and your current number of untested words and kanji for each category.
The completion date, after the first two weeks, takes your running average as of the last two weeks to calculate the end date. This is to allow for variations in pace over longer periods of time; i.e., if you are busy for a while and can only do fifty reps a day, that slow period doesn’t forever after push your completion date back past what it actually will be.