how to do it may slightly vary with your distribution.
A general purpose instruction: First you will have to know which name your IDE drive is assigned. You can tell it either from the way you plugged it in (hda is usually primary master, hdb primary slave, hdc secondary master, hdd secondary slave). Another way is to view the output of dmesg to get the name. For example "dmesg | grep hda" will show you the boot up messages that hda gave. Try it also for hdb, hdc or whatever to get the name, I guess you will recognize your ide model.
That you get "a bunch of errors" gives me the idea that by plugging the harddisk in you might have changed for example the name of your cdrom drive, but that's just a wild guess. Use "dmesg | less" to view all error messages and eventually post them.
After you know the name you will most often create partitions, format them and append a line for it in /etc/fstab so that it gets mounted at boot time.
Use cfdisk as root to partition your disk. Just type "cfdisk /dev/hdc" to partition the hdc device.
You should reboot at that point after you created the partitions.
After that use mkfs.whatever to create a file system on any of the partitions. Let's assume you created hdc1 (primary partition) and hdc5 and hdc6 (two logical partitions), than you could for example create an reiserfs file system on hdc5 with "mkfs.reiserfs /dev/hdc5". Please take care to point mkfs.xxx to the right partition.
Then edit your /etc/fstab. You will probably be able to copy and modify an existing entry, hm, from any /home /var etc. partition. Fill in the right filesystem type (in this example "reiserfs") in the third column of /etc/fstab.
That should do it. I hope there aren't any errors, but you should get the idea.