Buy Tickets

I want to buy a ticket for myself and my friends/family How can I buy tickets for my child(ren)? I want to buy a ticket for myself What are the opening hours of the physical ticket office? How much does a Standard Liege match ticket cost? Are play-off matches included in my season ticket? I forgot my ticket at home on match day. What can I do? I'm limited to 10 tickets in my online transaction, but I'd like to buy more, how do I go about it?