In a battallion,regiment,brigade, and higher command HQ what S, G and J mean? (S=Section or sth else?)?

Answer 1

if you mean like S-1, G-1, and J-1

it means:

S is for staff section at Battalion and Brigade level anything with a commander less than a general

G is for a General staff, a general commands the unit.

J is for Joint staff, it has members of all services and is designated as a Joint command by the civilian government normally for a specific purpose.

There is also a C for coalition it has members from several nations on the staff.

Answer 2

yep that's right.