A Complete Beginner, What Should I do In SH4?

First of all, hello everyone! I hope everyone is having a safe and cozy day.

So, some days ago I started to watch a streamer playing SH3, and this way I discovered the serie itself. Now, when I asked the streamer how should I start SH3, he told me to "never play without GFX installed."

I installed SH4 today, and I don't know if I need to directly jump into it. I have never played Silent Hunter games myself. Are there any "Don't go into game before installing this" mods for this game? Are there any mods that drastically improve my gaming quality?
Thank you.