Only one Pokemon may be put to sleep on the opposing team at a time, if not induced by a move such as Rest

 

That mine when opponent pvp use rest first and their pkm is sleeping, i cant use another move (sleep powder, hynoposis) to any different pkm??

I believe that is allowed.

Sleep Clause - You lose if, at the end of your turn, two of your opponent's Pokemon were put to sleep by a move you used but were not forced into, and neither have had their sleep removed since then.

The clause basically means that if you have already put a Pokemon on your opponent's side to sleep and it is still sleeping, you can't put another one to sleep.

A move you were "forced into" is a move you must use because all other moves (that cannot inflict sleep) are disabled (by Choice item, Encore, or some combination of Taunt, Disable, Torment, and lack of PP) and you cannot switch (due to trapping moves, trapping abilities, Ingrain, or having all other Pokemon be fainted).

A move you used includes moves called by Metronome, Sleep Talk, Assist, Me First, or Copycat. It does not include Magic Coat or Magic Bounce.

Rest, used by either player, is never counted by this clause.

 

Hope this helps, this is smogons rule