While the Gentoo Handbook contains almost every step needed into making a working Gentoo installation the kernel configuration step can be quite confusing for a new user. Enabling proper hardware support and turning on all the useful features can be daunting if you're not a developer or simply haven't encountered the kernel configuration before.
A good way around it is to use a generic kernel. genkernel provides a way to build a default kernel but I often find its default configuration to be either out-of-date or missing some important bit.
So, if you want to get started on Gentoo quickly you might as well use my kernel configuration which is based on the Fedora kernel and as such follows an everything-and-the-kitchen-sink approach. It supports practically every bit of hardware out there, will work on desktop PCs, laptops and servers, and includes important security features such as KPTI. The downside is that it's very large and will take a long time to compile.
To use it install the latest stable sys-kernel/gentoo-sources package (4.14.x), copy the configuration file under /usr/src/linux/ and rename it to .config then proceed to build the kernel as usual.