The bootloader as Grub loads the kernel. The kernel is extracting itself and starts itself.

If something goes wrong the kernel stops with a panic messages. Sometimes the kernel hangs. In this case it is worth to wait, maybe it is just a blocker and the kernel continuous after a while (e.g. after 1 min). If the system comes up, dmesg will show the trouble and its first column is the time, so the hanger can easily be found.

When the kernel comes up it starts the first program passed by the bootloader.

Traditionally it was /sbin/init for SysVinit system.

Today most Linux systems have replaced init with /usr/lib/systemd/systemd

To have the Linux kernel showing one tux per processor (if there are not too many processors) enable framebuffer support. Select therefore VESA VGA graphics and Framebuffer Console support.