For the game go to http://www.retrogamemaps.com/forum/downloads.html

Click on Line of Sight Vietnam maps, files, and tools
Once there download Line of Sight Vietnam MOD

From Google download as follows

Click on Download anyway

Once downloaded open with WinRAR archiver

You can get the WinRAR archiver at http://retrogamemaps.com/downloads  On Page5. Download Wrar361
Run setup and you can use it on all downloads from the site. It works as a free version.

Now install Line of Sight - Vietnam Mod.rar It should install to C:\Program Files\Infogrames\Line of Sight - Vietnam

You will see the following message. Click Yes and carry on

Once Installed there will be a shortcut on the desktop to play the game

Double click the shortcut and as the game loads up click on the screen then on SINGLE MISSION
Then on Mission1, click right arrow at bottom to load Map.

Mission1 will start. Carry on to complete the map and each map can be loaded after each other up to Mission12

To play online with others you should follow instructions to open ports as follows.
PORTS TO OPEN: IN YOUR OWN ROUTER AND FIREWALL:

forward or open ports 60001, 60002, 60003, 13242, 50000, and 50001, all UDP. This applies to all Nfusion games.
You can normaly get instructions for different routers on the internet and for opening ports in your firewall for different versions of Windows too. This does not have to be done if you are playing at home on single player.

That is for single player mode but you can play online with a group of friends by one of you hosting the game
 and giving the other players an ip address to link to to join the server so that you can play a set of multiplayer maps
which can be downloaded by all of you to install and join the server. On average there will be up to 12 players or more.
To get your ip address type myip in google and press enter. 80.4.94.242
Your public IP address
You now have your ip address to give to friends when you host a game.
To host a game simply start the game and go to HOST GAME You can click on Name and delete
Player then enter your username which can be anything you like.

When the screen comes up it will have a few things to alter.
Click on Game Type: to get to Cooperative. Now you can see all the missions from 1 to 12.
Next, Max Players to 12. Now go to Item Deletion Time: and alter it to 120.
This gives you 2 minutes for weapons and other equipment to stay on the ground giving you time to
collect it when you are killed and respawn.
Go to Dedicated Server: and leave it at No so you can join the game with others.
If it is set to Yes you cannot join your game unless you join from another computer.
Go to List on GameSpy: and change to no as GameSpy servers closed down some years ago.

With Mission1 at the top click to next screen.

Click to next screen to choose your health and, or Weapons and Items by dragging them across the screen.

Click to load the map.

Send all your friends your ip address to put into the top of the screen as they load Multiplayer.
Now if someone has started a server and you have been sent an ip address then start your game and go to Mutiplayer,
Join Game.
At the top of the screen at IPAddress type in the ip address you were given, click arrow bottom right to join the game.

To download other maps to host or join in Multiplayer,
Go to http://www.retrogamemaps.com/forum/line of sight vietnam2.html. Scroll down to Cadet 1 to 14 and
click the link to download these maps. Click to Download. Select Save File. Close browser when downloaded.
Double click your download then when opened double click the Cadet 1 to 14.exe to install the maps.

Other players must also have the same maps installed to the game before you can host or join in Multiplayer.
To play the maps chosen you have to delete all Missions in the Multiplayer screen and add your list of maps
One by one.

Once they are all deleted click on the plus sign and start to select the set of maps to play online and add them one at a time.

Once you have them all loaded click arrow bottom right and the first map and the server will start and you and any
friends can join the game.