Working through Create Beautiful Documents (better than Word) using TexStudio on Ubuntu Linux.

Entered:

    \documentclass{article}
    \usepackage{amsmath}
    \title{My Document}
    \author{Glenn McDavid}
    
    \begin{document}
        \maketitle
        Hello world!! This is a numbered equation:
        \begin{equation}
        2x+3=2
        \end{equation}	
        and this one is unnumbered
        \[
        2x+3=2
        \]
    \end{document}    

Went to “Tools” menu. Chose “Build and View” which worked. There is also “Compile” which did not show the output when I tried it the first time.