Spawn user created models/sprites:

With the model_spawn and sprite_spawn entities you can have your own models spawn into the map.

model_spawn

This entity obviously spawns models, the two fields:

usermodel = The path to the model, the models/mappack/user/ bit is hard-coded, meaning you can't change it, so you only need to put in the directory name i.e. torch/tris.md2 (note the direction of the slant)

userframes = This is how many frames there are in the model OR how many you want the model to cycle through, i.e. a value of 5 would make the model cycle through frame numbers 1, 2, 3, 4, 5 continuously (NOTE: All models will cycle through the animations forever)

sprite_spawn

This entity spawns sprites, there is only one field for this:

usermodel = The path to the sprite, again, the sprites/mappack/ is hard-coded, you just need the little path to your sprite i.e. bfg/bfg.sp2.

The sprite will cycle through ALL frames, you cannot pick which ones to show, and it is done continuously.

IMPORTANT: For some reason both model_spawn and sprite_spawn in the same map don't seem to like each other, and stops one of them from animating, you can try yourself, but it didn't work for me.