Linux kernel source code can be found in https://www.kernel.org/

Download extract and enter to the kernel directory

Type these commands step by steps in your terminal.(Choose the appropriate version you needed instead of linux-4.7.tar.gz )

wget http://www.kernel.org/pub/linux/kernel/v4.7/linux-4.7.tar.gz
tar zxvf linux-4.7.tar.gz
cd linux-4.7

make menuconfig will select the features required for the kernel. Old kernel configurations can be copied by using old .config file and executing make oldconfig. Also we can use make xconfig as a graphical version of the configuration tool.

Build the dependencies, compile the kernel and modules.

make dep
make bzImage
make modules
make modules_install 

Alternatively if you want to reconfigure the old kernel and re compile it, execute the below commands:

make mrproper
make menuconfig
make dep
make clean
make bzImage
make modules
make modules_install

Then copy the kernel, system.map file to /boot/vmlinuz-4.7

create a .conf file with the below content

image = /boot/vmlinuz-4.7
label = "Linux 4.7"

Then execute lilo -v to modify the boot sector and reboot.