Just downloaded Musescore

If you're just starting with MuseScore, why then downloading the old MuseScore 2.3.2 rather than the latest 3.2.3?
For some reason the Palettes and the Inspector are not open, they are by default, but can get closed/opened later, via F9 and F8.

First of all though go and get MuseScore 3.2.3, then have a look at the handbook

Besides the handbook, most of the basic operations have not changed in a long time, so basic getting started tutorials from version 2 still work in version 3. The tutorial page (https://musescore.org/en/tutorials) was made in version 2, but you can learn a lot from them.

Indeed, not good to start with an older version, better to get the current. But either way, that's not what it should look like when you first start it up, it appears you have closed the palettes window as well as the Inspector.

Here is a good basic tutorial:

https://school.masteringmusescore.com/courses/366102/lectures/6267305