When timing yourself on any Rubik's cube, you want to use THIS website. First, you choose your cube. Then, you perform the given scramble. These scrambles are the official scrambles of the WCA. (World Cube Association) After you have scrambled the cube, you can hold the space bar to start your timer. When you have finished solving the cube, you hold the space bar down again to stop the timer.
cstimer.net calculates your average for you. But if you didn't use that website, then you have to add up your times (don't add your best and worst times), and divide by how many remaining times you had. That is your average. You may see AO5 and AO12. Those mean Average Of 5 and Average Of 12. (also, if you get to 100 solves, it does calculate an AO100 of you!)
When racing in the WCA, you have 15 seconds to look at your cube before you start your timer. To enable this feature in CS timer, you have to go to options, then you press timer, then you change the option of "use WCA inspection" to always instead of never. You can also enable CS timer to warn you when you have 8 seconds left in your inspection.
DNF stands for 'did not finish'. This can happen when you run out of time in your 15 second inspection, it you stopped the timer before you finished the solve, or if you start solving before the timer starts. If you accidentally do a DNF then you can press on your time that you want to make a DNF, and you can press the spot that says DNF to make your solve a DNF.
When you scramble up your cube with the given scramble, you always hold the white side on top, and green side at you. After you have performed your scramble, you may not know if you did it correctly. To see if you did do your scramble correctly, you can press tools in the top left part of the screen (it looks like watches), change your function to 'draw scramble', and then you can check if your scramble was correct by comparing what it shows to your cube. Remeber to scramble with white top and green front!
You can make Sessions on CS timer, this means that you can make a different group of solves in case you want to use a different cube. If you run out of sessions, you can add more by pressing the session number you are on and then you can scroll down to a different session.
The WCA (world cube association), is where all the records are made for cubes. If you want to see the fastest time to solve WCA puzzles, go HERE, press on results, and press on records. You can explore this website because it is really cool and interesting.