Get the name and guild of a player in the #1, #2, or #3 spot. (Pick one that doesn't use special characters to make it easier to google them.)
Google this way:
playername partofguildname Site:swgoh.gg
The guild name is honestly optional, but might be helpful if someone has a common (like one of the game-defaults or a common modification of a real life name like, "gamerjohn") player name. If you do use part of a guild name, pick a part that uses no special characters, preferably at the beginning.
Through google, you should find the Swgoh.gg profile of the player, and if you look at that profile you get their ally code. Once you have their ally code, message them in game and ask if there even is a fleet shard chat -- and if there is, how to join.