I just replaced my alternator, now my radio doesnt work and battery won't charge

Your alternator is not made to run the vehicle 100% without a battery that is functional. Always start with having a known good battery installed in the vehicle fully charged before even testing the charging system. Some folks think that the battery only serves to crank the starter over, and that's entirely false. With the high amount of vehicle electronics over the last 25+ years, a solid 12.5 - 12.7 volts or so is required at a steady level to keep all electrical components including the engine's processor steadily operational. Your alternator, when functioning correctly (which we truly do not yet know, as it has not been tested...we assume it is OK because it is "new") will put out amperage to recharge the battery and operate vehicle accessories at 12+ volts -- but only when you are driving down the road at a normal speed with the engine revving at maybe 2,000 RPM and above. At idle, this just doesn't happen, and your battery is relied upon to maintain consistent power to the vehicle as the alternator is not able to produce raw power as needed. The other point is that the alternator produces power via internal coils and brushes, and this is not "stable" power like a battery; so together, they maintain constant voltage and amperage to keep things rolling along as they should. Regarding the radio -- fix the rest of the starting and charging system before looking at that. But you simply must resolve the battery draining issue, or you will have continuing battery failures and replacements.