Charging system?

So I just bought the truck it's been sitting for like 10 12 years something like that it's got a hundred six thousand miles on it it's a 4 cylinder 2.5 l with a 5-speed manual two wheel drive people I got it from Lost the key so I had to put an aftermarket ignition in it as easiest way for me to do it got it running ran down the road all of a sudden shut off. Check the alternator you need an alternator so I got an alternator put that on still won't charge the battery so voltage regulator external voltage regulator put it in starts right up runs as battery goes down drains out. Where do I go next? Any ideas fellas and ladies?