How to calculate flexural yield strength?

I'm trying to learn some new engineering, so if something I ask doesn't make sense -- remember I'm new to this.

I need to calculate how much force a part can take before breaking.

Material: resin (Flexural Yield Strength: 6752 psi) - (Tensile Strength: 3390 psi) - (Density [lbs/gal]: 9.64) - (Durometer Hardness: 78) *** if this isn't enough info, substitute your own material as an example.

Force: variable (make any up), applied by rivets onto contact surface (refer to attachment link for specifications) *******/b2d7T87 (for higher quality pic)

If someone could at least give me the steps needed to calculate this.