Sharding standalone MongoDB
About MongoDB 3.6 shards, from the official release notes: 


  Starting in 3.6, shards must be replica sets.


When you add shards, should be something like:

sh.addShard( "rs1/mongodb3.example.net:27017,mongodb4.example.net:27017,mongodb5.example.net:27017" )


With a status like:

--- Sharding Status ---
sharding version: {
   "_id" : 1,
   "minCompatibleVersion" : 5,
   "currentVersion" : 6,
   "clusterId" : ObjectId("5be0a488039b1964a7208c60")
}
shards:
   {  "_id" : "rs0",  "host" : "rs0/mongodb0.example.net:27017,mongodb1.example.net:27017,mongodb2.example.net:27017",  "state" : 1 }
   {  "_id" : "rs1",  "host" : "rs1/mongodb3.example.net:27017,mongodb4.example.net:27017,mongodb5.example.net:27017",  "state" : 1 }
active mongoses:
   "3.6.8" : 1