Need layout help on Joomla 4 template

I have a Joomla 4 template at http://thresholdtestingsite.com/newwet/index.php that is using a Joomlart template. I need ongoing help with some layout and functionality. For example, I want to incorporate some css from our old website. Look at the food images at https://worldexotictravel.com/hedonism-ii-resort/hedo-food-drink I added Prude Beach Grill to the bottom of http://thresholdtestingsite.com/newwet/index.php/resorts/hedonism-ii.

I copied all of the css to the same path, but don't know how to 'connect' it. I also want some help with other layout issues.