How to "SOC"?

hi, can someone tell me how to SOC scenary?
The wiki explains only the aspects of SOC but not how to really SOC an object(scenary)(I want to make only a tree, with one sprite.)

Because you are creating something nearly identical to an object already in the game, you can take a shortcut here and find a scenery object to copy... for the sake of the explanation, we'll use the bush from GFZ.

Start by Copying the object configuration of MT_BUSH(object 120) to a freeslot that you don't think will be used by most other SOCs(especially ones built in to character wads, such as Hinote.wad; SOCS built in to other levels are less of a priority). Change the Spawnstate of your newly copied object to the Freestate you intend to use for your scenery object, and the Mapthingnum to the thing number that your object will use in the wad editor. Save, and we'll move on to the next step.

Next, open the State Edit dialogue, and go to the Spawnstate that you just selected for your object. Select your sprite from the dropdown(unless you have any other custom sprites, it will probably be 243 - SPR_F001 (Free slot)), and set frame to 0 since this is the first sprite in the set. Because this is the only state you want your scenery object to use, set tics to -1, and Nextstate to 0. Just in case there is an soc out there that uses this slot, we should also set the action to "none" and the action parameters to 0 so that it will overwrite anything from the other SOC's entry, preventing a glitch with your object. Save, and you're done! Test the SOC with a map that has the object placed and see if it works.

thank you, but can you explain how put my sprite in the "dropdown" that you speaked above?
note: I have understood what do you have explained, but what I don't undertand is how to associate the sprite with the freeslot.

You don't. Freeslots always use fixed sprite names, in the Fxxx format, I think.

So you would make your sprites F001A1, F001A2A8, F001A3A7, F001A4A6 and F001A5, for instance. Or, just F001A0 to make it show for all directions.

The frame is the subsprite, so if you change that you can use the other sprites. Frame 0 is A, frame 1 is B, and so on in the order of the ASCII character set.