You can replace the system home page completely with any web page of yours.

Login to the system web console

Click the link "Manage Meetings"

Locate the section "Use My Page as the System Home Page"

Save the system web console login URL, which you will need in order to access the system console later.

Prepare your own page by placing proper URLs or forms for users to host and join meeting.

Input your page URL to "My system home page URL".
To implement Step #5, follow the instructions below.
There are two ways for users to host and join meetings: click URLs (or buttons associated with the URLs) on your page or submit forms on your page. Using URLs is the easiest way for customization. Using forms gives you a better control of customization.
URLs:
Host meeting URL:
https://your_meeting_server_address/as/wapi/goto_downloader?role=host
Join Meeting URL:
https://your_meeting_server_address/as/wapi/goto_downloader?role=attendee
Forms:
Host meeting form:
-- the essential HTML code:
<form action="https://your_meeting_server_address/as/wapi/goto_downloader" method="post">
<input type="hidden" name="role" value="host">
Email Address:
<input type="text" name="email" value="">
Password:
<input type="password" name="user_password" value="">
<input type="submit" name="sumbit" value="Host Meeting">
</form>
A better formatted complete sample code can be downloaded here.
Join Meeting URL:
-- the essential HTML code:
<form action="https://your_meeting_server_address/as/wapi/goto_downloader" method="post">
<input type="hidden" name="role" value="attendee">
Meeting ID:
<input type="text" name="meeting_id" value="">
Meeting Password:
<input type="password" name="password" value="">
Your Name:
<input type="text" name="name" value="">
<input type="submit" name="sumbit" value="Join Meeting">
</form>
A better formatted complete sample code can be downloaded here.