The FTB Forum is now read-only, and is here as an archive.
To participate in our community discussions, please join our Discord! https://ftb.team/discord
Check out the instructions in the microblocks.cfg file. It is pretty self-explanatory. You will probably want to use something like NEI which can show you the IDs of items in-game.
Here's a chunk of mine. It won't apply to you since our IDs will be different, but you get the idea. Also, this will likely change with 1.7 since IDs will not be implemented the same way.