Normally you change the scale with the UV map in your 3d progam -> scale the uv. Otherwise you could also open the material - add a texure coordinate node - connect it with the uv from the texture sample - now you can change the size of the texture 
Normally you change the scale with the UV map in your 3d progam -> scale the uv. Otherwise you could also open the material - add a texure coordinate node - connect it with the uv from the texture sample - now you can change the size of the texture