For the torch-holder: just make one with few small brushes, make them func_group… and u have your own prefab.
For the flame: you don’t find that texture because its a shader. Look at a map where there are flames used (Caen for example), and see whether they are in the shader. I don’t know enough about shaders/haven’t done one yet so I can’t help u further. For a very start maybe just make an oddly shaped brush and give it a light-emitting light orange tex (u need to do a shader for that yourself of course).
For the flickering light effects on the walls around the torch you need dlights. Right-click into some window, then select dlight. Read the info on that entity closely, you ll find a lot of info in there. Try all the stuff out too (preferably in a box-map cuz u there s a lot to test and u always need a full LIGHT-compile).
Warning though: that kind of light is real bad for gameperformance if used too often and in places where i can be seen from lots of (outside)spots.