1. Install updates and after that install the next packages

sudo apt install network-manager network-manager-config-connectivity-debian network-manager-gnome network-manager-openconnect network-manager-pptp

2. NetworkManager does not start automatically, so you need to add it to the /etc/rc.local file.

sudo nano /etc/rc.local

…. the contents

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
NetworkManager start
exit 0

… save and quit
Ctrl o
Ctrl x

3. You also need to add nm-applet to .icewm/startup file.

geany ~/.icewm/startup

… a contents

#!/bin/bash
nm-applet &

… save and quit
Ctrl o
Ctrl x

Now you can reboot the computer or run
nm-applet &
sudo NetworkManager start

Edit 27.2.2023 Some reason in some installations nm-applet does not allow edit or create connections (somekind of polkit problem as need to install package like lxpolkit).

A dirty fix is to run nm-applet as root

gksu nm-applet

Edit 28.2.2023 antiX has a custom package installer and via that installer NetworkManager can be installed. The installer installs the next packages

libelogind0 libgck-1-0 libgcr-base-3-1 libgcr-ui-3-1 libmm-glib0 libndp0
libnma-common libnma0 libopenconnect5 libpkcs11-helper1 libpolkit-agent-1-0
libpolkit-gobject-1-0 libpolkit-gobject-elogind-1-0 libstoken1 libteamdctl0
libtomcrypt1 libtommath1 libtss2-esys-3.0.2-0 libtss2-mu0 libtss2-sys1
libtss2-tcti-cmd0 libtss2-tcti-device0 libtss2-tcti-mssim0
libtss2-tcti-swtpm0 mobile-broadband-provider-info network-manager
network-manager-gnome network-manager-openconnect
network-manager-openconnect-gnome network-manager-openvpn
network-manager-openvpn-gnome network-manager-pptp network-manager-vpnc
openconnect openvpn policykit-1 policykit-1-gnome pptp-linux tpm-udev vpnc
vpnc-scripts

Anyway via that package installer, NetworkManager requires gksu-nm-applet for editing connections and the installer does not set networkmanager process to start and startup, so they need to write by hand.

#####################################################

NetworkManager in antiX 23 runit

1. Install updates and after that install the next packages

sudo apt install network-manager network-manager-config-connectivity-debian network-manager-gnome network-manager-openconnect network-manager-pptp

2. Make a runit service

sudo mkdir /etc/sv/networkmanager

…. create script

gksu geany /etc/sv/networkmanager/run

… which contens is

#!/bin/bash
exec chpst -u root /usr/sbin/NetworkManager

…. make it executable

sudo chmod +x /etc/sv/networkmanager/run

… link to /etc/service

sudo ln -s /etc/sv/networkmanager /etc/service/networkmanager

3. Edit $HOME/.desktop-session/startup file by unticking nm-applet line

geany $HOME/.desktop-session/startup

Reboot and run nm-applet as root at once for adding connection

gksu nm-applet

Edit: 7.5.2024: Now nm-applet seems to work without gksu. Maybe updates has made some changes? Polkit maybe?

apt list --installed | grep polkit

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

libpolkit-agent-1-0/bookworm,now 123-1.0nosystemd2 amd64 [installed,automatic]
libpolkit-gobject-1-0/bookworm,now 123-1.0nosystemd2 amd64 [installed,automatic]
libpolkit-gobject-elogind-1-0/bookworm,now 123-1.0nosystemd2 amd64 [installed,automatic]
libpolkit-qt5-1-1/stable,now 0.114.0-2 amd64 [installed,automatic]
polkitd/bookworm,now 123-1.0nosystemd2 amd64 [installed,automatic]

Edit 8.5.2024: libpolkit-qt5-1-1 package gets NetworkManager working without gksu.

Read also: https://puolanka.org/goto/network-connection-using-nmcli-via-script/