Sorry if this is a stupid question - ftm and I suspect I may getting many things wrong 
How the flip do you "put a baby down to nap"? Dd is 5 months, I'm pretty sure she needs to nap after being awake for 2 hours (gets grumpy after this time) but the only reliable way I've found to do it is to walk her in the pram.. I'm going for 3 + walks a day, every day, and tbh it's getting a bit wearing! Very occasionally she'll fall asleep while feeding and we'll manage to put her down without waking her. If I try to put her down awake (usually in the pram but in the living room and just push her back and forth) she'll suddenly perk up and get chatty, then start complaining and eventually cry so we pick her up. She falls asleep eventually but only after being awake (and unhappy)for 3-4 hours which is not ideal.
Please help!