[hkwerf]

> Is there a recommended hardware and step by step guide for those new to this?

What exactly are you planning to do? OpenWrt is quite flexible. There's this https://openwrt.org/toh/buyerguide.

> Can you do mesh networks?

Yes. Note also https://openwisp.org/ if you want to do a whole fleet of OpenWrt routers.

[rubenbe]

I've always found openwisp to be tailored to massive fleets of OpenWrt routers (100+). Not really for a home setup where you have a handful of devices (5-10). Alternatives are welcome since I haven't found anything yet.