I was looking for some advice on how to play Dark Souls on PC with keyboard/mouse. I want to start the game(s) and I'm not comfortable using a Gamepad, so... Is it possible to finish the games without a gamepad and can you teach me to play that game with keyboard?
Sure, Dark Souls can be played using the keyboard and the mouse.
If you can use keyboard/mouse in the meaning of if it's harder: there is no objective answer for it. Some players might prefer using the gamepad, some may prefer using the keyboard/mouse combo. If you want to hear my opinion I went better with keyboard/mouse maybe because I don't play with the controller a lot.
You also requested somebody to teach you how to play it with the keyboard. You can find the standard key mapping for controlling the character on this wiki page. It's the basic WASD controlling that is used for most of the games where you control a character. The camera angle is controlerd and attacks are started with the mouse and it's buttons.
Dark Souls 1 actually works horribly with the mouse.
The game did not port the controls properly, and when you use the mouse it moves around as if you have a grid, so you lose a LOT of precision control.
There are 3rd party mods for it to make it simulate an analog control, but you get weird artifacts like acceleration. It still ends up being better than vanilla mode.
The experience with keyboard and mouse on the vanilla game is absolutely atrocious. It is borderline unplayable.
There are older versions of the mod that does not work with the latest patch, so you'll have to hunt around for the latest release. It's been years since I played DS1, and I don't have access to my usual system, so I can't look up how I setup my system, but I did get quite far before playing DS2.