Archers, chariots, slings, spears (thrown and melee spears).
From wiki:
2686 BC – 2181 BC (Egyptian Old Kingdom)
"Old Kingdom soldiers were equipped with many types of weapons, including shields, spears, cudgels, maces, daggers, and bows and arrows. The most common Egyptian weapon was the bow and arrow. " The same types of weapons would be used for a loooong time before and after this time period.
Wiki says chariots were used as early as 3000 BC.
This isn't as far back as you are trying to go though. What sources do you have that say the 1st armies were 3500 BC? Which civilization did they belong to?
Babylon was founded 1867 BC
The 1st assyrians were around 2334 BC
Sumeria goes back to about 2900 BC
Early bronze age is 3300 - 2100 BC --- before that it was likely stone weapons...poor bastards.
If we can nail down a culture, we can see what weapons they used....but really they were all probably about the same kinds as listed above! Those were primitive times. Everyone had bows (starting around 10,000 BC). Maces are just glorified clubs, and spears are also prehistoric. I think going with chariots as a "technology" for this far back may be your best bet!