i use skritter to practice writing hanzi with the correct stroke order. it is a well designed program. skritter uses spaced repetition. there are decks for the course i'm taking, which is handy. it's a bit pricey (15$/mo), but for the moment i think it's worth it.
i don't have access to the play store, so i reached out and they sent me a link to a page with apks, which i really appreciate. they are stored at https://files.skritter.com/android/.
§chinese sentence structure
subject verb object, like in english
* i eat an apple
* wo chi pingguo
===== location =====
in english, location goes at the end of sentence (i eat an apple at home). in chinese, location goes before verb.
* i at home eat apple
* wo zai jia chi pingguo
===== time =====
ditto with time, put it before the verb.
* i yesterday ate an apple
* wo zuotian chi pingguo
===== location and time =====
you can put either first, but most common is putting time first.
* i yesterday at home ate an apple
* wo zuotian zaijia chi pingguo