How install Spain's digital certificate on Arch-based Linux distributions?

Requirements

Execute the code below. ‘base-devel‘ is a package group that includes tools needed for building (compiling and linking). It is not necessary for a basic install, and many users don’t need to install it. If you find it useful, you can either install it as part of your basic install, or later.

sudo pacman -S --needed-base-devel

ConfiguradorFNMT

git clone https://aur.archlinux.org/configuradorfnmt.git
cd configuradorfnmt
makepkg -si

AutoFirma

git clone https://aur.archlinux.org/autofirma.git
cd autofirma
makepkg -si

Installing the certificate in Mozilla FireFox

1. Open ‘Settings‘.
2. Search for ‘Certificates’.
3. Click ‘View Certificates’.
4. Open tab ‘Your certificates‘.
5. Click ‘Import‘.
6. Select your digital certificate and enter the password.