I haven't used frontpage for a long time but from what I can remember there is an icon in the top toolbar and you should be able to click that and select how many rows and columns you want. If there is any more help you need please post.
I think you can insert by clicking insert table. Why are you still using frontpage? I think fronpage is not friendly user and not for webdevelopment. I recommend dreamweaver it's the best web editor for me.