The synthesis tools are quite complicated and they are more of an art. I would compare using them to a tool chest with many different tools and you need to use them in the right order to get a good result. You can try reading the userguide and it will walk you through it but depending on how much you are familiar with synthesis tools in general it can be quite difficult to follow. You can also try by reading existing tcl files, but I would only recommend that if you are already very familiar with the competitor tools.
The best way and the recommended way would be to take a course. The ones in class at Cadence are quite expensive, but they also offer licenses for pre-recorded courses, you can watch them directly from their website. There is a whole set of courses on their digital physical tools. You will have to ask your system administrator. Alternatively, there are also some courses from university extension programs and they are much cheaper. I took one from UCSC-extension several years ago, but it was on Synopsys.
If courses are not available, you could see if you can get ahold of the RAK (rapid adoption kit). Cadence has several of them on different tools. They might have one introduction on Genus. They also have some tutorials. You need to download them from the Cadence support site, again, ask your system administrator and they can try to download it if they have not done so yet.
As for books, I have not seen any. You will find things on writing SDC constraints, there was one on P&R and happened to use Innovus, but that is it. The books tend to be more generic to apply to any tool.