How do space probes find there way to planets

And them ones that land with parachutes to the planet.

Do they use a control pad or something?

There paths are calculated ahead of time, and then they are given just the right thrust and spin to send them on their way shortly after take-off. Often they use close passes by other planets to speed them on their way. Orbital mechanics is as close to an exact science as we have.

As far as navigating from the earth to the vicinity of the planet, they don't navigate themselves, they are guided there with a lot of help from controllers on earth, at JPL in the case of most US spacecraft. After being sent in the direction of their target planet by the guidance system of the launch vehicle, the spacecraft is tracked by the Deep Space Network and periodically throughout the trip the spacecraft is commanded to perform what are called midcourse corrections, small maneuvers with their onboard propulsion systems to correct the trajectory and put them on course for their target. As for landings, I assume you mean on Mars since that is where most American spacecraft have landed, that is controlled totally by onboard guidance and computers, the round trip communications delays are too long to allow any effective control from earth. For example, when Curiosity landed on Mars about a year ago, by the time we received the first telemetry on earth as the spacecraft started to enter the atmosphere, on Mars it had already landed.

NASA (Or the relevant space agency) works everything out on paper first, this means that they can send the probes out with pre-programmed commands which tell the probe when to burn its engines, when to rotate etc. As for the ones which enter other planets atmospheres they likely use sophisticated auto-pilots which cause certain commands to trigger when specific factors are met such as reaching a specific velocity or altitude.

To add on to what these other people have already said, they are also mostly self automated. There is no way that someone back on earth could control them, because of the speeds and distances involved. Just for example, it takes almost 10 minutes for information traveling at the speed of light from Earth to reach Mars. And if one of these space craft were to go behind a planet, facing away from Earth, then there would be no way for us to directly control them. Instead, many orbital space craft are on per-planed paths, and the mars rovers use a combination of indirect commands and advanced computers to move around.

Space probes are the first versions of (unmanned) space-craft launched by man.
No space-craft is designed till now that can maneuver or is controllable. We don't have that technology yet.
As a comparison - we are in the same state as before the Wright brothers in the field of aviation was in.