1) download and install kernel sources an software
(opensuse leap 15.3)
zypper install kernel-source-vanilla
zypper install kernel-devel
cp /boot/config-5.3.18-150300.59.43-default  .config
zypper install bison bison-lang flex libfl2 libfl-devel m4
zypper install ncurses-devel
zypper install openssl
zypper install  libopenssl-1_1-devel      
zypper install bc
zypper install grubby
	
2.a) compile kernel and modules
make 
make modules

2.b) (optional) prepare/install kernel and modules
make modules_prepare
make modules_install

3) adding entry to grub bootloader:
sudo grub2-mkconfig -o /boot/grub2/grub.cfg
grubby --set-default /boot/vmlinuz-5.3.18-150300.59.43-default