Tunnels are not spawn points. New SLs keep placing tunnels instead of garrisons, then cannot figure out why nobody can spawn or why the tutorial will not advance. You need a garrison (or another linked tunnel) first. Connecting happens on the tactical map, not by walking up to the hole.

Who Can Place a Tunnel

NVA Only
Roles that can place: Squad Leader, Commander, Recon Spotter.
No Supplies Needed
Place in friendly, neutral, or unlocked enemy territory. Locked enemy sectors will refuse it.

1Build the Tunnel

Cooldown is 10 minutes after Patch 1.3 (was 5). Plan placements. You cannot spam a new network if the first one dies.

2Connect It (the step everyone misses)

You cannot link garrison to garrison. There must be a tunnel in between.
Tutorial "Connect a Tunnel to a Garrison" specifically: Do not run to E5. Command already placed a tunnel there. Build your garrison, open the map, click the E5 tunnel icon, then click your garrison. Walking toward E5 fails the training timer.

3How You Actually Use It

4Key Decisions

Garrison first or tunnel first
Garrison first
If you need a spawn. Tunnel first only if a garrison already exists within connection range and you want a free fast-travel hop. Community consensus: garrisons first, tunnels as the highway.
Where to put the next node
100 m min, ~400 m max
Use a relay tunnel if the front is farther than one hop. Hide the entrance. US players hunt and dismantle them.
Who reconnects
SLs link, Commander re-routes
SLs can create links. Commander can delete a connection (click the line on the map) and re-route when the front moves.
Tunnel cap
12-15 tunnels max
Do not burn the team's tunnel cap on redundant nodes. Plan the network.

Fight Demonstration

Common Mistakes to Avoid