Hi Michael,
This is an good question, because if you can do something with one routine instead of multiples, I’m all for it!
The answer is yes, you can do everything with one routine. I just tested it with my bedroom light.
Here are the steps.

1. Open the Alexa app, select “More” at the bottom, then “Routines”
2. Make a new routine by pushing the “+” button in the top right corner
3. Enter a routine name, then select a trigger under “When this happens”, for instance, you might select “Schedule”, then “At Time”, and set it to 9AM.
4. Then go back to the routine you’re creating and add an action. In your case, you could select “Smart Home”, then “Lights”, then pick your Office Lamp. Select Power to be “On”.
5. Then, add another action. In your case, it might be “Wait”, and select the time period you want the light to be on.
6. Then, add another action. In your case, select “Smart Home”, then “Lights”, then pick your Office Lamp, and set Power to be “Off”.

It’s a bit tricky to get the hang of the first time, but once you set it up, you can test it out and tweak things until you get them working the way you want. Hope that helps!