How much time and days spent for first order
There is no requirement of days. Seriously, it’s a market place and not a game where you get coins for amount of days spent in the game.
All depends on YOU! You can get orders on a very first day or might never get orders.
It depends on how good your gig is
Fiverr is not a magical place where you only need to set a gig, and buyers will come knocking at your door.
I just checked and there are 7464 gigs for converting pdf to Word or Excel. Furthermore, 6429 of these gigs are gigs made by level 0 sellers like you. It would be best if you spent some time looking at the gigs of level 2 and TRS sellers that offer this service. What makes them stand out from the level 1 and level 0 sellers? When you figure that out, then you can improve your gig to be attractive to more buyers.
NOTE: Do not copy anyone’s gigs. If you do, you could lose your account.
As said above, there is no time requirement. I have found I get more messages when I am online than when I am offline. I keep Fiverr online while I work on projects in order to show available, but I wouldn’t say it’s been a huge driver for sales.