How do I apply a texture to a whole model, instead of each face?

I’m trying to apply a texture to a cylinder but, I have no idea how to apply to it as a whole, it keeps assigning the texture to only one of it’s faces at a time

You either drag & drop it. Or choose it from a drop down of that mesh. Or select the material in the content browser and hit a white arrow next to the mesh:

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How are you doing it?

Dragging and dropping selects only one face, and selecting the whole model doesn’t give me the option to apply a material

Ah, you’re editing a brush.

Either select the material in the content browser first and then drop the brush into the level - it will have this material applied automagically.

Or convert the brush to a static mesh and then apply material:

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