Good advice from oiler baby. Shhh/pat doesn't work for everyone and it takes a long time to take hold, it would be extrememly difficult with older children to look after. Just concentrate on appropriate A times, a good winddown and not overtimulating during the last part of the A time, and naps should sort out soon. The a.m. nap "develops" between 3-4 months and the p.m. nap between 5-8 months.
Here's the link to w2s--https://babywhispererforums.com/index.php?topic=64168.0