Once the IDE is installed, run it by double clicking on the icon. A new sketch will open up. A good first step is to adjust the preferences file. This is found under File/preferences, as shown in the figure below.
Here is the window that opens up:
Once this window is open I find it useful to adjust the settings. I like using a large font size for the sketches to make it easier for me to read the screen. Experiment with values for your computer. I prefer 16 font size.
The following boxes should be checked:
Display line numbers. This adds line number to each sketch and makes tracking and referring to the code so much easier.
Verify code after upload. This will check the code after loading into the Arduino.
Save when verifying or uploading. This is very important. When using computers to create any sort of content, the first lesson you learn is, you cannot save your work too many times. By clicking this box, the sketch is automatically saved whenever you click the verify button or upload the sketch to the Arduino.
However, if you click this box, it means that if you happen to open a sketch and make any changes to it, your changes will over write the original sketch. This makes it important to always save your sketch under a new file name whenever you start out.
The first step after opening a new sketch or opening an existing sketch is to do a Save as, under File/save as, as shown below.
Use a directory location that is convenient. The IDE will automatically create a folder with the same name as the file and the file itself with the .ino extension.
Once the preferences are set, we can open up a sketch.