You should probably start reading here:
RV Electric and Solar by Jack and Danielle MayerThe above link even recommends a "phased approach" that might work for you. It is a good place to start reading about what you want to do - add solar to provide electricity to operate your TT.
After you spend some time reading the first site above you will have lots of questions that people on this forum would love to help you with.
You should also start reading here for more in-depth details of your 12 Volt battery powered systems in your trailer:
The 12 volt side of lifeThe 12 Volt Side of Life site will help you understand much better how your trailer electrical systems work.
Now if you want to have a fun and educational reading adventure, this site:
HandyBob's Blog - Making off grid RV electrical systems work
has some really great information but you have to do a lot of reading through his rants about bad solar installers and equipment. Handy Bob has strong opinions and is not afraid to state them very bluntly. And you can learn a lot from reading his site.
And don't hesitate to come back and ask more questions on this forum. We have lots of people with deep solar experience that love to answer technical questions and provide advice.
Good luck getting started on your solar project.
Ed