A CD is 700 Mb. The memory card is 1 Gb, which is 1000 Mb. So it will hold about as many pictures as fit on 1.4 CD.
If you use the detail view of My Computer or Windows Explorer you'll see the size in bytes of each picture. If that's on the average 1,000,000 bytes (1 Mb) there will fit some 1000 of them on the memory card. If they are bigger, it will be less, of course.

If you put the CD in the computer, a box might pop up. Or not, depending on your settings. Whatever way you choose, go into My Computer or Windows Explorer to continue.
There's no need to copy the pictures FIRST to the hard disk, THEN to the memory card. You can do it directly, in one step. And you can use any way of copying you like: drag and drop or copy/paste are the usual ones. As long as you use one CD, you won't get a "memory card full" error.
If you ever want to know how full the memory card is, just right click on it, choose properties and it will be shown.

There's nothing wrong, of course, with copying the pictures to your hard disk in between. If you have them there, you can view them also on the PC without needing the CD. Your choice here.

Hope this helps.