Re: my tablet dose not have google play store, installing apk file not working. help me.
Amazon AppStore has about the same apps Play Store does (a few less, but more all the time) for the same prices, including the free ones. It's as safe as Play Store. As soon as you try to download an app (using a browser), it'll set you up to install Appstore, their app for their store. It's trivial and painless.
Be careful where you get your apps, especially if you have to download an apk file directly - some of those sites are good sources of viruses.