I am a new modder this is about my first mod ever a house.
I am trying to create a new ayleid container, I go onto the container list make a new container, ID (zzzzchest so its at the bottom) it name it
put a book and a key in I made. all good.
Now when I try and put it into the world it comes up with a Yellow diamond with a exclamation mark in it.
please help iv'e had this problem with my mods to
:brokencomputer:
:flamethrower: help me burn my problems please

The yellow symbol means that the editor cannot find the model you have selected, a few things you might want to check -

Try dragging out a few different models into the render window, if none of them work you have a serious problem with your CS.

If you notice that its mainly models with a "SI" prefix it means that your trying to use shiving isle's models but the editor hasnt properly loaded the content. (make sure you tick it in load files) - Same for the other official addon packs.

When your making a new container, make sure a .NIF file has been set, if you see a button saying "Add nif file" it means that that container has no model.

Try this - Drag out a container into the render window to make sure it works, if it does, right click on it in the list, choose edit and it will bring up the property window for that object. If you change the ID it will copy everything about the object including its model path. Then find the new ID you gave it and drag it out, hope that works.

Thanks for that it is the NIF file but.
whenever I try and set a NIF file all I get is the mod NIF files, not the vanilla oblivion files
any ideas?

Technicly you shouldnt need to set any .NIF files unless your using custom models from outside the game. What you need to do is copy the model you want to use. You do that by Editing an object, in your case a container, and renaming the ID. This will clone the model and make it seperate from the one already used by the game.

If you really really want to set a .NIF file you need to use a tool like BSA Commander and extract the "Meshes.bsa" file in you oblivion directory. It contains every mesh used in the game. You would normally only use this if you retexturing an object too.

so I use a container, change its ID which duplicates it?
So I can use it however I want

be sure to answer yes when asked "Create a new Form"