Veasna says to you, "That which shall make the ideal, real. Make sure that the bracers I gave you have been attuned, or are otherwise 'No-Trade.' Once you've made sure of that, simply take this yellow gem, right click on it, select 'Use,' and then click on the bracers. You won't be able to do this while you're wearing them, so be sure to put them someplace safe in your inventory. A few seconds later, and the process will be complete! Show me what the result is."