I think that if they haven't replied in one month, you can send an email to just ask if they got your submission. If still no reply, I think it's safe to say that it's a rejection, and you can bring your pitch elsewhere.
With traditional publishers, they usually ask for X weeks to review, with X being whatever they deem necessary for their team to go through their read pile. After X weeks, they say you can send a follow-up email. Since Tapas doesn't have that clause on their website, I think one month would be a decent amount of time to wait? I could be wrong, though!
Would love for anyone with experience (i.e. whether getting accepted or rejected!) to chime in?