Silt soil can be good soil with little fertilizer needed. It will hold water well. A downside, is that it often compacts well.
The first step, is to have a soil test done. Here is the link to the Colorado State University Soil, Water, Plant testing lab. http://www.soiltestinglab.colostate.edu/
The soil test will give you the actual soil composition and at least tell you the pH of your soil. The soil test can tell you how much compost you might need. It will also tell you what fertilizers you may need. The pH is important to know what type of compost you can add to the soil, and how much might be needed.
Below are two links to some information on amending silty-soil.

https://homeguides.sfgate.com/ways-amend-silt-loam-soil-46600.html

https://agverra.com/blog/silty-soil/

You may decide the best option it to build raised beds for a garden. If the area is larger, you may decide to use compost.

After looking over the information, if you still have questions, get in touch.

Best of luck,

Marvin

It is difficult to amend this soil. If you are putting in a garden, consider raised beds or amend the areas at ground level similar to a raised bed. If you leave a walk way, you do not need to amend that area.
That said, you can amend the soil with compost, manure, aged pine bark, or other vegetable matter. Vegetables will often grow in the soil. Often this soil has a high pH of 8.0 or above. Adding sand will often create a worse problem.
You will need to have a soil test for Nitrogen-Phosphorus-K(Potassium) and pH at least. This will help you determine what amendments you can consider.
https://extension.colostate.edu/topic-areas/agriculture/managing-sodic-soils-0-504/

https://extension.colostate.edu/topic-areas/yard-garden/choosing-a-soil-amendment/

Good luck,

Marvin

Currently the Colorado State University, Soil, Water, Plant Testing Lab is closed. I would consider Weld Labs or American Ag Lab as options to test your soil.
https://weldlabs.com/ag-soil/?gclid=Cj0KCQjwrJOMBhCZARIsAGEd4VExC0C0Dka6YRC6Cu5xzU2kjlGkNGwspZN_kvzRG9CyW78Bu3yeoTAaAtm1EALw_wcB

_Weld Labs)

https://www.amaglab.com/ (American Ag Lab)

Marvin