If 3%, foget it. Nothing will happen except a little fizzing action.
If 60% or more, adding a combustable material to hydrogen peroxide is a quick way to commit suicide. 90% (or more) hydrogen peroxide is a high explosive all by itself.

It is possible to make high explosive using hydrogen peroxide, but I will not tell anybody how. The resulting material is VERY sensitive and highly dangerous. Commercial dynamite is far easier to use and safer.

There are MANY ways to make poison weapons, but I will not post any details. Most of them are damned dangerous. Only a very few are safe enough to make and transport. Of course, if one is a suicide bomber, safety would not seem to be a big issue.

IF I were going to make a bomb, I would use commercial explosives, not home-brew.