It sounds like you have run down your battery. You hear a click but there's no crank and the dash lights go out when you try and start, that's a classic low voltage situation. Either your battery is old and won't hold a charge, or it was drained while you were working on the car. To reiterate the good information in the comments trunk, hood or passenger compartments lights are the most common culprits. Or, if you were working on the car for a long time, like weeks, it could be the battery just losing charge over time.
It takes a lot of energy to start a car, and you need to run your car after starting it to replace that energy. You started your car while it was on jacks, then turned it off right away leaving your battery depleted.
The solution is simple: jump the car, then drive the car to charge the battery back up. I'd run it for at least 20 minutes, maybe longer as the battery was flat. You could also buy a battery charger and use that to charge the battery, which will take longer.
As for how to avoid that in the future the simplest way is to disconnect the battery when you work on the car, first the negative and then the positive terminal. If the battery isn't connected it can't be drained. If you are going to work on your car for more than a week at a time you should consider buying a trickle charger as your battery will naturally run down even if it's not connected.
A multimeter would be a very good purchase, it's a piece of test equipment that you can use to read AC/DC voltage, amps, resistance and other measurements which can help you diagnose common problems in your car. Ordinarily I suggest buying quality equipment, but the difference in price between cheap and known brands is huge, so unless you are made of cash an inexpensive one is the way to go. I'm amazed with what you can get for $10 in the multimeter space.
To test your battery you would turn your multimeter to DC volts, usually a symbol which is a V with parallel lines, then touch the probes to the battery terminals at the same time. The number that goes on the multimeter screen is your battery voltage. A charged battery would be at least 12.5 volts, yours is probably far lower than that. If your battery is that or higher but you are still having trouble starting then you have a different problem.