If you just need any 2.6.34-kernel, you might head over to koji and try to find a precompiled one for you version of fedora. You can install it as root after downloading all required rpms with
yum localinstall kernel-*.rpm and it will automatically appear in Grub.
If you need to modify the kernel, it is best to also start with the distribution kernel and modify it to suit your needs. There is an extensive howto in the fedora wiki.
Lastly if you really need to start from scratch with the sources from kernel.org, you have to download the source and extract the archive. Then you have to configure the kernel. For this, say
make menuconfig for a CLI or
make menuconfig for a graphical configuration. You might want to start with the old configuration of the running kernel, see http://unix.stackexchange.com/questions/2496/recompile-kernel-to-change-stack-size.
When you are finished configuring, say
make to build the kernel, then
make modules to build kernel modules.
The following steps have to be done as root: Say
make modules_install to install the modules (this will not overwrite anything of the old kernel) and finally
make install which will automatically install the kernel into /boot and modify the Grub configuration, so that you can start the new kernel alongside the old one.