Just started working from home and honestly not sure what I should be buying

I recently started a remote job and I’m trying to put together a proper home office instead of working from my dining table.

I’ve been watching setup videos and reading posts here, but now I feel even more confused because everyone seems to recommend something different.

The one thing I’m leaning towards is getting a standing desk since I’m not used to the constant sitting and I prefer some activity. We had standing desks at my previous office, so I’m already used to switching between sitting and standing during the day.

I was also thinking about getting some kind of shelf or bookcase nearby because I already have random notebooks, chargers, papers, and other stuff starting to pile up. I might just keep a small side table next to the desk for the extra stuff instead.

Other than that, I have no idea what’s actually worth spending money on. Monitor arms, desk lamps, ergonomic chairs etc.

For those who’ve been working from home for a while, what would you buy first if you were setting up a workspace from scratch today? Just trying to avoid wasting money and get the basics right the first time.