Generally, Jijimon is stated to be ancient, so it would know how to fight. It uses a stick mostly, but the technique carried over from using a stick to using a sword, based on how I saw it fight in Tamers.
Also, there is some proof that Digital weapons don't bind to a Digimon until they get them, so if these were taken after being forged, then they could be unbound to any Digimon, thus usable by a human.