When you sign up, Ludoteka sends you an email message to validate the address you have given. You have two options to do it:
If you have not received the message email, the first thing you should do is to verfiy that you have writen your email address correctly.
If you check that it is well written you can always request a new message. You can also do it from Your profile.
If you still cannot find it, check your SPAM folder. If you find it there, remember to enter the address email@example.com in your contacts.