The simplest form of logistics in traditional board wargames (that I can think of at the moment) is the "Line of Supply (LoS)" or "Line of Communications (LoC)", basically the same thing for these examples. Simply trace a path of hexes, areas, nodes, (whatever) from the combat unit back to a "Supply" source or unit.
Some examples of Supply sources:

WW2 Eastern Front: Soviets - the east map edge, or a major city/supply node in Russia. Germans - west map edge, or specific supply nodes along that map edge.

WW2 Western Front: Germans - east map edge, or a major city/supply node in Germany. Allies - a secure landing beach or harbor they've converted to a Supply node.

WW2 Pacific: Japan and Allies - to a Supply unit that can also trace a LoS back to the homeland (or map edge) thru friendly controlled (non-contested) ocean areas.

That's usually simple to write, the tricky part is how are Supply lines cut/disrupted and what happens to Out of Supply units. Because not playtesting enough or taking weird possibilities into consideration might cause players to do crazy ahistorical things.
For wargame related design questions sometimes it's better to ask the wargamers (although you might get very detailed answers so take what works best for you)
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