I found a post that describes how to do it. The missing parts is telling the laptop how to reach the cluster:
$ lxc remote add cluster0 <ip-of-a-cluster-node>
$ lxc remote switch cluster0
$ lxc launch ubuntu:22.04 c1
$ lxc list
+------+---------+------+------+-----------+-----------+----------+
| NAME | STATE | IPV4 | IPV6 | TYPE | SNAPSHOTS | LOCATION |
+------+---------+------+------+-----------+-----------+----------+
| c1 | RUNNING | | | CONTAINER | 0 | lxd0 |
+------+---------+------+------+-----------+-----------+----------+
Note: I still need to set up a network for containers on the cluster, hence the lack of IP addresses in the list above.