Regarding peeling the sweet potato: Peel the sweet potato if your baby is brand new to finger foods, I always find that if the baby is 6 or 7 months old they have a problem swallowing the skin. Once they become used to finger foods (around 8-9 months) then you don't have to peel anymore.
Cut the sweet potato in half, and then cut up into 1/2 inch thick long strips, or about the size of your finger. If the piece is very long, you can chop them in half again.
Place sweet potatoes directly on baking sheet. Pour olive oil on top and stir to coat them. Make sure they are single layer and not on top of each other.
Bake for 24 minutes, flipping them half way, so they don't stick to the pan. Check after 24 minutes and if they’re soft, they’re done. My rule is if a fork goes through very easily then they're done. If they are too hard, add a couple of minutes until you get the softness consistency you want.
Allow to cool and then give a couple sweet potato fries to baby to eat as finger food.
If you want to serve this as sweet potato mash, place in a bowl and mash with a fork. The sweet potatoes are already soft so you don't really need a food processor to mash them, a fork does the job.
You can store leftovers in the refrigerator for 3-4 days. I heat them up in the microwave, making sure they are cooled down before serving baby. For long term storage, you can place them in freezer bags and freeze.