Are you looking for playtesters for your game? Put up a post here.
Just remember to include:
When you’re looking for - when are you available?
Are you still looking - edit the post when you’ve finished testing
How are you going to test? - Tabletop Simulator? Tabletopia? Roll20? Skype? In person? Semaphore?
How many players do you need? - Do you need two or three other players? Fourteen? One hundred and nine?
What kind of game is it?
What’s the essential experience?
And remember, people are more likely to test your game if they think their game will be tested too. Don’t be shy about offering to playtest other folks games or signing up to their requests!