1. Know how to locate and open unity in your computer. Unity installs in program files. It also creates shortcut on desktop for launching. Should you update unity, be sure to check the shortcut is for which version. Double click the unity icon to open.
2. Unity opens the list of previous projects done. If you are working on new project, select new.
3. Give the project name and select your preferred location. Keep the location path as short as you can and be sure to note the folder location.
4. Select 3D or 2D depending on the project you are working on. 3D is world space project using x-y-z coordinates.. 2D is x-y.
5. Click create project. This will take some time and the window might disappear from view.
Unity will now open a blank project with camera and light.
Test your project by clicking play button. A blue screen is displayed.
Click on play button again and it returns you to earlier screen. Also be sure to check the games tab, it opens blue screen but note the play button is not highlighted.
This way you know the mode you are in.