You can get them by just "hovering" of your forum and picking up the f=XXXXX where XXXXX is the forum / category id.
For example, this forum is located in this category:
https://vborg.vbsupport.ru/forumdisplay.php?f=227
Therefore the "Category ID" is 227
The forum itself is here
https://vborg.vbsupport.ru/forumdisplay.php?f=228
Therefore the forum ID is 228
So if I wanted to make this appear under category 227, i would set categoryID to 227 and forumid to like 999