Sorry if this is long, i've just spent a couple of years away from cryptocurrencies so am trying to regain access with limited understanding.
A few years ago I bought some Litecoin and dogecoin (after researching how best to keep them safe etc). After this I had a laptop HDD die about 3 times and have changed phone several times so am having difficulty getting access.
I have an app on my phone 'Dogecoin' which I used to use to check my wallet with but as I have changed phone several times and the app has just transitioned across i'm not sure if the keys in it are my old ones or if it creates new ones when you open it on a new phone. Currently it has 2 keys starting with a 'D', both 34 characters in it, so I am trying to check these.
On my hard drive I have found a file which is 'doge-coin-wallet-backup-2015-09-07'. The file is just a mass of text, i'm guessing this is an encrypted private key? The file has no extension and when, on Mac, I make sure it is displaying file extensions, I can still not find out the file extension.
My question is, using the two keys on the wallet app and this file, how can I try and get access? I am really poor with the terminology (different types of keys) and also using commands to do things so if anyone could help i'd be very grateful.