First off any Star San left in the fermentor actually become yeast food.
Secondly, There really are no "signs of fermentation" if you are using a bucket...i.e. you can't see the krauzen forming and falling...
If you are referring to
airlock bubbling, get out of the mindset that that equals fermentation, or you will be stressing out over nothing.
Bubbling or lack of in the airlock is
not a good indication of fermentation occuring...If that's what you mean by "no signs of fermentation," then it could (and probably is happening) and you aren't even aware of it...There's way too many variables that can come into play in terms of airlock bubbling to use that as an indicator.
So many new brewers don't get bubbling and panic and want to repitch the yeast...when it turns out that everything is copacetic.
You could have for example and bad seal between the grommet (or stopper) and the airlock, or the lid on the bucket isn't fully tight and gas is getting out elsewhere besides the airlock, or the stopper and mouth of the carboy and that would appear slow, while fermentaion is actually occuring rapidly... Or the little bubbler in the airlock could be sitting a little crooked, or become weighted down with tiny co2 bubbles and need to build up a good head of gas before blurping again.
Even having the airlock leaning slightly askew affects it.
So as you can see airlock activity varies, and should not be used a a sign of speed or lack of fermentation.
I have had beers that fermented beautifully without one bubble in the airlock, and I have had others that sounded like a machine gun from the get go, and I have had others that needed a blow off tube...each beer is different....
You can't assume anything with beer...except that the yeast know what they are doing, since they've been doing it for several thousands of years, and it is really hard to ruin beer.
The airlock is just that, an airlock that attempts to release the pressure of CO2 without letting anything in....But for the above reasons it isn't the greatest tool in the world.
If you are brewing in a carboy, you can see the activity that you wouldn't get to see without openning the bucket.
The hydrometer is the only true indication of fermentation, and since it has only been a few hours it's waaaayyyy to soon to be taking one.
Thirdly, fermentation can take up to 3 days to start. There's a sticky expalining this in the beginner's forum.
https://www.homebrewtalk.com/showthread.php?t=43635
There's actually another great thread I'd recommend you read.
https://www.homebrewtalk.com/showthread.php?t=54362
This is where patience and trust comes in...trusting that the yeast know what they're doing (which they do, they've been doing it for several thousands of years.)