First check with 'iw list' which adapters supports “mesh point”:

Supported interface modes:
 * IBSS
 * managed
 * AP
 * AP/VLAN
 * monitor
 * mesh point
 * P2P-client
 * P2P-GO
 * outside context of a BSS

After you can setup node with:

WIFI_INTERFACE=wlan0
MESH_ID=edge
NODE_IP=10.1.100.10/24
iw dev $WIFI_INTERFACE interface add mesh0 type mesh mesh_id $MESH_ID
iw dev mesh0 set channel 4
ip link set dev $WIFI_INTERFACE down
ip link set dev mesh0 up
ip addr add $NODE_IP dev mesh0

→ Remember to set different IP on each node.

You can check status of your mesh network with:

iw dev mesh0 station dump | grep Station
iw dev mesh0 mpath dump
iw dev mesh0 station dump | grep bitrate

On debian 12 you need to stop wpa_supplicant and NetworkManager. Disabling link setup rules is also needed.

sudo systemctl stop wpa_supplicant.service
sudo systemctl stop NetworkManager
mv /lib/udev/rules.d/80-net-setup-link.rules /lib/udev/rules.d/80-net-setup-link.rules.norules
sudo systemctl restart udev
sudo udevadm control --reload-rules

sudo iw dev [WLAN_INTERFACE] interface add mesh0 type mesh mesh_id [MESH_ID]
sudo ip link set dev mesh0 address [SET_MAC_ADDRESS]
sudo iw dev mesh0 set channel 4
sudo ip link set dev [WLAN_INTERFACE] down
sudo ip link set dev mesh0 up
sudo ip addr add [IP/MASK] dev mesh0

• https://wireless.wiki.kernel.org/en/developers/documentation/ieee80211/802.11s