There are lots of details involved in adding an inverter.
Here is a link to a website with very good basic info about RV electrical systems: The 12volt Side of Life (Part 1)
Note that there are 2 parts to the website, so be sure to click on part 2 at the bottom of part 1.
The above website is not going to tell you "how" to install an inverter. It will give you lots of good info to understand the 12V side of the RV, including the batteries, battery charging, solar and solar panels, converters and inverters.