So, I don't think your descriptions are actually too much of a problem so far. Like at the end of the day, this is a bitesize format and while I've got a total hard-on for description in my own writing, most people on tapas put stock on characters and plot. (I will drop a few description tips at the end, though, if you would like to work on them!)
Reading your prologue, the first thing that jumped out at me was the pronouns! Like ... despite the fact it's first-person, I think after the first mention, I'd like to be reminded of Henry's name a couple of times, and also to let me ease into it being first person because I, personally, am not that familiar with it so I expect third person (this is not be critiquing first person btw). So, just replace a couple of those he's and his with henry and henry's - not all! just where it feels right. It won't take away from your flow at all, I promise!
So, for description! your flow is nice. Especially for that prologue, don't break up your flow for the sake of describing his office in minute detail. Personally, I rarely do that anyway unless I have a character entering a room or I want to set a scene for mood, and then, let's face it, we aren't all JRR Tolkien, those hills don't need ten pages. Spend a paragraph on something new, a sentence or two on something familiar to the character, and when you do, focus on specifics.
Don't talk about the exact dimensions or shape of the room unless it's specific, talk about the way the light reflects off the mahogany panelling or a fire crackles in the hearth. Or perhaps you have somewhere more ominous: a forest, mist skulking between the trees and the musty stink of rotting vegetation in the air. These details are what bring scenes to life. Also notice, I don't use sight alone - how does it smell, taste, sound. Temperature. You feel these things, so do your characters. It's essential your descriptions are coloured by your character's perception.
My personal trick for description is work it in to what you already have. You've done this already with the desk, papers, spilling the coffee cup - these are the details you want. I have one example for this, and I would like to specify that I'm not saying that this is the place for expansion or that you need these details, only as an example of how I like to work description into action:
Your line:
He lowered his gaze to the floor and fidgeted his hands at his sides. "I'm worried about Lance."
With description:
His gaze dropped to the wooden floorboards, elegant fingers fidgeting at his sides. "I'm worried about Lance."
Might I also add that the mere fact you show feeling through this body language throughout your piece is excellent anyway! I'm only using this as an example of my point and this probably doesn't need the description.
(oh my days why do i keep writing these walls of text)
So in short: description is about detail! Work it into your action! Your writing is already good, keep working on your craft!
Wait also seriously, I just read the first line of your second chapter and that bit about purple petals is lovely!! the whole passage is brilliant description!