I need help w/early Roman formation and Marius.

[Hasdrubal]

Here's what I know from reading books mainly Polybius. The early manipuler system consisted of hastati, being the front line. Principes being the 2nd line and triarii being the third. With velites being up front to throw their missiles/projectiles. What I need if someone could explain is some explanation of the group.

I know a century consisted of 60 men that were led by two centurions, the furthest right one being senior. You had the optio in the back to keep formation in line and a signifier which held the banner. Two of the centuries would make a maniple and I believe you had 10 maniples in the front for a total of 20 centuries which would be 660 men?

How were the men placed in the centuries? Was it 10 men side by side, 6 deep?

Does any have a drawing or ms paint that would help me see each individual century, in a maniple, in a cohort, up to a full legion. I'm not completely understanding Polybius and it would be more helpful to see a visual.

Also the Marian reform, how did that all change the lines? Did they keep the centuries?

Thanks!