The assembly should be self explainable, the feet should be pressed into the body as far as possible, the slots became narrower to the end so the feet don't loose to easy.
I suggest printing the body laying flat and the feet upright. Be aware that the left and right feet are symmetric but not equal. The model is optimized for a 0.6mm nozzle and 0.25mm layer height. But I tried to match the dimension also for 0.4mm nozzles. Support should not be required.
To fix the fan on the body you can use default fan screws as well as M3 or M4 combined with a nut. To insert the filter slightly bend it over the top clamp and slide it into the body, afterwards you can push it under the clamp on the top. The filter dimensions should be ~120x120x10mm.
I hope you enjoy the model :) - after testing several downloaded models and wasn't satisfied by any of them I decided to create my one one. The key advantages over many other solder fan stands are:
The author hasn't provided the model origin yet.