Which nuts and bolts?

Well, I just got my 1995 honda civic, but the front bumper was messed up. When I purchased a new bumper and started unraveling my old bumper, it had many different bolts on it? But what size nuts and bolts should I get for my new bumper?

 

use the old ones. or use the same size as the old should be 10mm 8mm or 12mm. depending

 

Without a doubt use factory bolts. It is an 8mm thread with cross head flat top.
As far as where the bumper mounts to the fender use the ever so famous 10mm hex bolts and nuts to match. Most salvage yards will give them away.

I can attach a pic if need be.