sanitize the house clean everything just everything and keep it room temperature or cool also sanitize her hands every day and sanitize your hands to she still sensitive so kids her age can you get sick very easily that happened to me with my daughter soon as I gave birth she started getting a little sick

Keep everything as clean as you can, and keep baby close to you. Your toddler might not understand, but you can always try the "you don't want the baby to get sick too, so don't sneeze or cough on baby" and make it a fun game for every time they do wash hands, etc. If it's just a cold there's not much the doctor can do. Just keep an eye out for anything that seems like more than a cold

take her to the Dr asap. keep hand sanitizer around 247, make sure you wipe down anything toddler touches and don't let her touch baby with bare hands.. try wearing baby on you as much as possible too