Simple host names - hostfile?

I am aware that I need static leases, and stuff.

What is the most simple way to assign such names? The list of static leases contains my boxes, but I can't ping them.
E.g. have a box with foo as hostname, with MAC address, IPv4 address, ... in the list. Instead of reaching it through ping 192.168.23.34, I'd like to reach it by its hostname, that is ping foo. Unfortunately, it doesn't do that; and neither does ping foo.lan for active leases.

I did a search and found some sources, but they were all command-line based, several lines, whatever. I was hoping to be able to associate a hostname together with its IPv4 address when creating the static lease.
Is this possible?

You can do it with just LuCI going to Network -> DHCP -> Leases -> Add:

Insert the hostname you want to assign, the MAC address, the IPv4 you want and toggle on Forward/reverse DNS.

Save and then Save & Apply.

Edit: Just to ensure you understand what I have tell you to do. I have guide you to set a static lease while also adding into dnsmasq a record that will be resolved even if the device has not yet ask for DHCP server.

You can also leave Forward/reverse DNS toggle off and unset the hostname, that way the dns record will only exist if the lease is in the DHCP leases file and allow you to change the hostname in the device and not setting a "fixed" one in the router.