Hi Ariel, I still learning but I think I can help you with this.
1. I'm going to the movies. -> 映画館を行きます。（えいがかん を いきます）
2. I already ate. -> 食べました。 （たべました）
3. I went running yesterday. -> 昨日私は走れました。（きのうわたしははしれました）
Japanese formal basic structure is SOV (subject, object, verb) instead of SVO (subject, verb, object) like English and Portuguese. For me, that is the only major issue for us, the logical construction is quite different but practice can solve it.
By the way, Japanese use a write system based on phonetics, that I think turns things easier to learn how to speak and all.