See also Artillery
The legionary's personal weapons were two javelins, a sword and a dagger.
The sword was very important. It was light and short (no more than 50 cm) so soldiers can use it for stabbing quickly.
The legionary wore his sword high on the right side of his body. This enabled it to be drawn underarm with his right hand without interfering with the shield which he carried in his left.
A soldier carried two spears to throw at the enemy. The spears were just over two metres* long and they were designed to bend and stick in the enemy's shield so he cannot use it to protect himself. They were difficult to pull out and will bend on impact, so they couldn't be thrown back at the attacking Roman soldiers.
* US spelling of all metre words is meter.
The pugio was a small dagger used by Roman soldiers as a sidearm. It was worn on left side.