How to build a kernel on debain 10

Dependencies:

apt install gcc libc6-dev libncurses5-dev binutils make gawk gzip coreutils grep zlib1g-dev flex bison git libelf-dev libssl-dev

Download the kernel you want build:
https://www.kernel.org/

Create your kernelConfig [.config] or copy a working old one.
If you use an old config, make sure you run the ´make oldconfig´ command to set all new modules to Y|N.

tar xfsv linux-5.3.8.tar.xz
cd linux-5.3.8

cmueller@debian ~ ll /boot | grep config-$(uname -r)
-rw-r--r-- 1 root root 147K Nov  3 18:44 config-5.2.0

cp /boot/config-$(uname -r) .config
make oldconfig

make menuconfig

If you need some specific driver you can look at the linux-firmware repo:
https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git

cd /opt/kernel
git clone https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git

Put the directory in the kernel config:
CONFIG_EXTRA_FIRMWARE_DIR="/opt/kernel/linux-firmware"

Build the kernel:

cd linux-5.3.8
time make -j8 bzImage modules

Install kernel & modules:

sudo make modules_install install

Reboot

Trobleshooting:

Problem:

make[1]: *** Keine Regel vorhanden, um das Ziel „debian/certs/debian-uefi-certs.pem“, 
  benötigt von „certs/x509_certificate_list“, zu erstellen.  Schluss.