Send them this link. When they open it you are both on the same board.
Waiting for them to join
Or have them type your code at Play a friend → Join.
Type the code your friend gave you.
Music: Minstrel Guild, Folk Round and Village Consort by Kevin MacLeod (incompetech.com), licensed under Creative Commons: By Attribution 4.0.
An iPhone or iPad installs from Safari’s own menu — there is no button this page is allowed to press for you.
It takes the lion for its icon, opens without the address bar — which is the only full screen an iPhone will give this game — and still plays with no signal.
It is also the only copy an iPhone will let tell you that somebody has challenged you. Turn that on in Companions once it is on your Home Screen.
Challenge them to a game.
Somebody challenges you.