By Cheetah
Now that we planned the mission, it is time to start developing! Let's start with the bulk of a mission, units; plenty of units! In order to place a unit, press F1 or select "Unit" on the right side (green button). Notice that the markers disappear, by pressing F6 or selecting "Markers", you can modify and display them.
We want to be able to preview the mission, to do so, doubleclick near the insertion marker. A Unit dialog (Image 1) will be opened, allowing you to select a unit to place on the map. Let's take a closer look at this dialog as it's one of the most important ones in the ArmA editor.
I suggest that you place a few enemy units inside the town, to make the player's life harder. What to place? An empty (side: empty) shilka named "tank", an enemy officer named "officer" and any number of soldiers which you want to have as opponents.
A few hints: holding LMB and SHIFT on a unit allows you to change its azimut. You can use CTRL+C and CTRL+V to copy and paste units. This allows for faster placement - note that you have to select a unit before being able to copy him.
You might notice a few blue lines connecting enemy soldiers upon placing individual soldiers (Image 2). This means that individual units are grouped, enabling them to exchange information about enemies etc. If you want to ungroup them, press F2 or select "groups", click on a unit and hold the mouse while drawing a line - release it on empty ground (Image 3).
In the right menu, note a button named "preview", click it to check the location of the enemy soldiers. You might want to move your character a bit closer to the town to prevent you from walking a minute every time you want to check the emplacement.
After playing a bit with the unit positions (Image 4), ungrouping all the enemies and checking the mission so far with the help of "preview", it is time to place a few objects on the map. Basically, you have already placed one, the empty shilka. We will now continue to place an enemy MG nest. Complete with sandbags and a MG ready to make your life harder!
Let's place the MG nest at the northern side of the fishing village, to make any direct approach a hard one. For some reason its icon is 180 degrees turned, we need to have the MG azimut at 0. Don't forget to switch the side to "East". We don't want to place an empty MG.
To protect the gunner, let's place a few sandbags around it (Image 5). To place them, select Side: "empty", Class: "objects", Unit: "wood fence". You can now copy and paste the sandbag element to add even more protection. I suggest placing four or five elements. You can change the azimut by typing in another number. Or, hold the LMB on a sandbag element, and hold SHIFT - then turn to change its azimut. You might have to "Preview" a few times in order to make the MG fit in the sandbag wall. Don't forget to make sure that the sandbags overlap each other a tiny bit to ensure maximum protection!
Advanced:
When you put the very first unit of a side on the map from the editor, that side is created. Meaning that if you don't place any unit of a particuar side in the map, the side will not exist and you won't be able to create any units for that side from any script unless you create the side first with createCenter. This is a quite common mistake when creating dynamic missions without units at the beginning on the map, so remember that: no units = no sides = no way to create groups for these sides, so you'll be forced to use createCenter to create sides first.
Solution:
If you want to create all the units dynamically and you don't want to mess up with createCenter command, then you need to add a single unit of each side, if required, set presence to 0%. Just place them all in the same spot and in careless mode, so they'll not interfere with the mission.