how to write in a CV that I won a prize along side two co-winners?
You can mention the prize you won along with your co-winners in the Awards and Achievements section of your CV. Here's an example of how you could phrase it:

[Year]: Co-winner of [Name of Prize] along with [Name of Co-Winner 1] and [Name of Co-Winner 2].
Make sure to include the year in which you won the prize, the name of the prize, and the names of your co-winners. You can also include a brief description of the prize if it is not well-known.

Alternatively, if you want to highlight your individual contribution to winning the prize, you could include it in the Experience section of your CV under the relevant position or project. For example:

[Year] [Position/Project]: Contributed to the team's success in winning [Name of Prize] along with [Name of Co-Winner 1] and [Name of Co-Winner 2].
I like the first example could you expound on it in more detail, please?