Measure the battery voltage - right across it's terminals - if you have battery voltage and no lights/etc., then the 200 amp fuse is blown or you have an open crimp/clamp/etc. somewhere.

If you have no battery voltage, the battery is dead. (This can be due to current draw when the car is sitting or <and I had this happen years ago> you have a broken connection between a battery post and battery plate. This can happen from age or from flexing of the connection between the battery post and plate - caused by weaknesses in the construction of the battery's housing.)

A voltmeter will tell you all you need to know, no mater what is wrong here.