An easy way to get started is to use a website template. As you become more confident and knowledgeable you will develop your own resources but if you are starting out, here is a good template to get you started:
You need to extract the contents before using it when it is downloaded. Move the extracted folder out of your downloads folder to a better place.
Again, there are many ways of editing web pages but a simple way to get you started is using a text editor.
The Putkeep Website Template uses a CSS framework called Bulma. You can look at the Bulma Documentation for more information about changing the styling.