For beginners in light novels, it could be a bit challenging. But as you progress through the story, you'll get more used to the writing style and the flow of the narrative. The novel also has a lot of character development and plot twists that can be both engaging and a bit hard to follow at first if you're not paying close attention.
The length of Mushoku Tensei manga varies, but it has a significant number of chapters. It's hard to give an exact count as it keeps evolving with new releases.
Well, first you need to figure out where to get the Mushoku Tensei light novels. If you're into digital reading, there are various apps and websites. But be careful with the legality of the sources. You can also ask fellow fans in relevant forums or groups. They might be able to point you to the best places to buy or borrow the novels. Once you have the novels, just start from the beginning. It's always a good idea to read the prologue first to get a feel for the story.