How to install Brave web browser for 32-bit lubuntu 16.04?

The accepted answer is obsolete because the Brave browser snap package has been discontinued. The current instructions for installing Brave browser in Ubuntu from the official Brave browser website are as follows. Open the terminal and type:

sudo apt install apt-transport-https curl
curl -s https://brave-browser-apt-release.s3.brave.com/brave-core.asc | sudo apt-key --keyring /etc/apt/trusted.gpg.d/brave-browser-release.gpg add -
echo "deb [arch=amd64] https://brave-browser-apt-release.s3.brave.com/ stable main" | sudo tee /etc/apt/sources.list.d/brave-browser-release.list
sudo apt update
sudo apt install brave-browser