When your model has a trophy, it will appear in the "selected" models. It also means that it will be temporary highlighted on the main page. The 6 newest models with a trophy can be seen on the main page.

These are random selected among good looking and qualitative builds. So, if you have built a nice model and spent quite a lot of time in it, and it doesn't get a trophy. Don't worry and keep building! 😃

Thanks for the clarification Sim. I will always keep building, Mecabricks has the best interface and brick selection of all the ones I have tried - best is that I can do this at work on quiet evenings without installing anything on the company computers haha.
I really enjoy doing this and I am in my thirties! Music and Mecabricks are good mix.

You are not the only one 😛
I can check and even update Mecabricks just with my browser from my work computer!

I got a few trophies but none of them have appeared on the front page or selected models

Hello legoporg. I don't see any trophys on the models on your page 😉

On the Jungle Raider, Podracer and Journey to the skull dungeons all have trophies when I go onto my library where all my models, the I go to when I log in

They do not. They are classified as official sets. That's why they have a set number in the top right corner. They do not have the trophy symbol in the top left corner.