Help with flex box

hi guys kindly refer to my link and assist with the section that contains my projects.
how do i have them all next to each other utilizing flexbox in a row using flex box but when i decrease the view port that they fall in-line into a column?
https://codepen.io/MJ-786/pen/vYWjrJW i want to have them lined up just like this https://res.cloudinary.com/dyahp6ca1/image/upload/v1646491989/Screenshot_22_ipjypz.png

i managed to find out what is wrong kindly advise on anything else that may be of benefit :slight_smile: