I started sleep training my two at around 7 weeks when they started getting more alert and stopped going to sleep so easily! I aimed for one nap in the cot at that age, and at first I was often spending the whole nap sshh patting. I normally went for the first nap of the day cos that's the one babies often find easiest, and at first we started with the moses basket in the sitting room where I could easily sshh them. After a while I think we moved to a dark room and played white noise to save me sshhing. It took a while to get them to sleep independently for every nap. I'm pretty sure they were both 12 weeks at least before it really clicked. Swaddling helped.
Most importantly though, I'd treat it as a long slow process and try to be relaxed about it. I read somewhere that babies organise night sleep from 0-3 months and day sleep from 3-6 months, so it can take a long time for a LO to grow into napping well. My neighbours little boy only slept for 30 minutes at a time til he was 8 months old, then suddenly started taking 2 hour naps. But those early months fly by really (I remember it doesn't feel like that at the time). Try to take time to enjoy your LO too