Hello to you Jolie! I welcome you to the RoleplayGateway site! It is wonderful to see new members being so enthusiastic and even being very helpful! Have some tea and cake! Or would want some cookies??? I could baked them for you! In any case, about your question Asperser had already answered it.
There are tabs that could be visible in the Roleplay you have joined. the "Posting" tab is wherein you could view all the posts that had been made and post your replies by clicking the link "reply to this roleplay" in the default location or if you could look at the upper corner, the word "Where?" could be seen and the choices of the places to post the reply of your character could be selected there. The long way would be, In the "Places" tab there are times that the creator of the roleplay would indicate different areas to be used in the RP. It depends entirely to you where you character should be located and the posts that you should see would have been divided by the places indicated in the RP. Choose that place and click the same link "reply to this roleplay". Post your reply. You could also post your reply in the "Activity" tab. The same process as the "Posting" tab.
RPG Rules Help Newbie Guide to RPGGuide to ChatRole Play AcademyOh, These are links that could help you get started in the site! I hope it would be very helpful to you! In any case, Welcome to the RPG community! I do hope you would have a great time here and create many new friends. Don't be afraid to ask questions to the staff and the members here. We are a very friendly bunch here! See you around and to have the chance to roleplay with you!