How do I reprogram my key fob on a 2000 dodge grand caravan?

[Jeff]

I took off the positive battery cable then when I put it back on, the red light on driver side under dash was flashing, not sure what this is, maybe something to do with anti theft not sure as van is new to me, anyway pushed in on red light as it is also a button and light went out but for some reason key fob will not work now and battery seems to be good, any help would be much appreciated as I do not have any info on how to reprogram key fob. Thanks in advance.