[Solved] Loading a number of different items onto wagons?

[ALittleGreenStone]

My outposts come under attack frequently. Segments of walls and turrets are damaged/destroyed, which construction bots repair and replace, or die trying.

That is, the two kinds of turrets, ammo, walls, gates, construction bots and repair kits, these are the 7 items (of different quantities) I'd like to put on a single cargo wagon (preferably, using one for each is what I'd like to avoid).

The problem is, the rate at which I'm producing walls are much greater than the rate I'm producing turrets, for example, so if I just use inserters, eventually the wagon will be filled with nothing but walls, with no space left for anything else. But there's no need to carry around that much either.

Is there way to load only a certain number of these items onto a wagon? A simple way, preferably?
Bonus if you explain it like I'm 5.

Thank you!

[sillyfly]

You can set filters to wagon slots, the same way you do for your toolbelt -
Use middle mouse button to select a filter for a slot. Middle mouse click on a slot with items in it will set the filter to the current item in the slot.
You can copy and paste these settings between wagons with shift+right click and shift+left click

[ALittleGreenStone]

Well, that was fast...And simple.

Thank you very much, it's exactly what I was missing!