Using Two Type of Granular

HI

Before I proposed my question, I have searched the forum, I got some useful information, but I still have some problems.

I need to use two or more types of granular materials (glass, iron ball), so I need to set the Youngmodulus, Poission Ratio, etc for both materials.

From the older topics in the forum, I found that it is NO need to use 'create_atom' command to create 1 and 2 types atoms. Instead, directly to use

fix m1 all property/global youngsModulus peratomtype value1 value2
fix m2 all property/global poissonsRatio peratomtype value1 value2
fix m3 all property/global coefficientRestitution peratomtypepair 2 value1 value2 value3 value4
fix m4 all property/global coefficientFriction peratomtypepair 2 value1 value2 value3 value4

I'm not sure about it. Am I right?

Tks for your help in advance.

Jian