Looking at what's in there currently, you'd write in your sessions sets and reps or time for the given exercise, i.e. 3 / 12, 3 / 60s, 30s, etc.
The issue with this way of recording things is that it doesn't really give you much room.
One of the key things when trying to get in shape is to get yourself stronger (everything is easier when you're stronger), and one of the best ways to do this is to constantly increase the weight that you're lifting.
What I'd suggest you do instead is buy a cheap notebook and record your workouts in that.
The benefits of a notebook are you can record a lot more information about weight, sets, reps and times, but you can also record other things that may be worth noting...
Didn't sleep the night before and really struggled with the workout? Write it down!
Stretched your chest at the start of the session and found the lat pulldowns a lot easier? Write it down!
Did some hip flexor work at the end of each session and found your squat for improved? Write it down!
Tried to perform a 50kg snatch without any training and dropped the bar on your neck and shoulders, popping one of them out of joint? Write it down! (To paraphrase Dan John, surgery is God's way of telling us we did something wrong).
This may seem like a lot of notes to take, but there's nothing quite as motivating as flicking back through your notebook at the end of a session and seeing that you just benched more than you ever have before.
Success leaves clues (another Dan John-ism) and everyone is different. Record things, look back and figure out what works for you.