On the command line, if you saved the commands - or got them from an instructional listing in the first place, you just paste the same set of commands into a terminal window.
Three comments from me:
(1) Regarding what Les wrote (above), I can say that the three Wiki "Kernel" HowTos have been written in such a way that the command lines shown in those articles *can* be copied (from a GUI) and pasted (into a CLI/TUI). I'm sure that same is true for many other WIki articles.
(2) We must not loose sight of what CentOS basically is. CentOS == RHEL less RH. A stable, server orientated OS. On the fora, we often see evidence that CentOS is believed to be similar to *other* distros (that are more suitable for laptops & "home" use) and that it, CentOS, can be loaded onto typical laptops or home PCs. Then the grumbling starts about the non-operation of a bottom-of-the-range NIC or video controller or how multi-media doesn't work straight out of the box. The complaints that really irritate me are those that end with ". . . . whilst 'foo' (or 'bar' or 'xyzzy' or 'y2') runs o.k. on my hardware. So why doesn't CentOS?"
(3) The CentOS-docs list. Anne, the last item I received was dated April 3rd.
Alan.