If plasma life did evolve in a brown dwarf and it did somehow become sentient, what kinds of things could they construct? Would they be limited to just pruning the bigger autotrophs or could they somehow make inorganic solid constructs? This can include buildings, ships, anything you can think of.
While plasma is often Very Hot, it doesn't have to be, additionally if they are able to control the plasma in order to exist, then they should be able to direct it from hitting what they don't want it to hit.
For your plasma creature to hold them selves together they would have to have some mechanism to manipulate electric/magnetic fields. If they are able to intentionally control the fields then they could "3D print" objects by layering up layers of what ever the plasma is made of, it would be similar a current technique know as plasma spraying, also related to sputter coating.
They probably wouldn't be able to do any organic chemistry type materials, as organic compounds general don't cope well with plasma. But depending on how well they can direct the coatings they may be able to layer up more complicated devices, like circuits.
While they wouldn't be able to "touch",ie no levers or buttons, they would still be able to move inside what ever they made, and maybe interact using the high conductance of plasma to connect different parts of a circuit.
hopefully that helps
From the definition of plasma
It consists of a gas of ions – atoms which have some of their orbital electrons removed – and free electrons. Plasma can be artificially generated by heating a neutral gas or subjecting it to a strong electromagnetic field to the point where an ionized gaseous substance becomes increasingly electrically conductive.
Since it's a gas of ions, you can't give it a proper shape. It will take the shape of the container where it is hosted.
And since it is highly energetic it will quickly eat away any physical container where you place it. I have used plasma to clean surfaces, it's pretty effective! You can only trap it in some magnetic field.
From the above it follows that a plasma life form would not be able to construct anything, it would just float around.
A plasma lifeform would, by its very nature, have very good control of magnetic fields. Likely also of electric fields and currents too.
It could likely build itself a very good telescope, or something functioning like the Internet. It would be utterly stumped even understanding a simple table, much less building or using one. Indeed, mere physical contact with matter in the Solid or Liquid phase would likely be very bad for its health!