Once the partition is created, we have to create a new file system on that partition. The standard file system used these days is the ext2 file system, but the socalled journaling file systems are becoming increasingly popular too. It's of course up to you to decide which file system you want to create, but because we have to assume and work with something, we will assume you chose the ext2 file system.
To create an ext2 file system, use the mke2fs command. The LFS partition is used as the only option to the command and the file system is created.
mke2fs /dev/xxx
Replace "xxx" by the partition's designation (like hda11).