Sure we can :) Though the question is a little confusing.. I'll try to answer anyways. From the context, it looks like you're talking about a 5E D&D bard. They get proficiency with 3 instruments of choice. This means they can use them (as a tool), and add their current proficiency bonus to the roll (along with a characteristic bonus, determined by the GM). Assuming you're using the 5E OGL sheet, you can set up your instruments in the tools section (bottom left IIRC). Don't ask me about musical instrument vs perform. I have no clue. However, bards can also use an instrument as a spellcasting focus. You don't add proficiency a second time. Instead, your spells will already have proficiency baked into them (attack roll, or save DC), assuming you're using 5E OGL (and probably for shaped sheet as well, it's been forever since I used it).
