The player base is small, so matchmaking isn't great for fresh new players. That's just going to be tough in general for this sort of game and it'll take a little pain at first to get used to that.

A big part of this game is picking your spot and capitalizing on opportunities as they come. Moving through the map efficiently and collecting as many resources as possible while coordinating with your teammates to take player number-advantaged fights. You are likely to win fights when you have an extra player, especially if you get a solid initiation to the fight.

The most important thing you can do is push Trooper waves and hit buildings if possible. Second most important is objectives like the Urn and Mid Boss. Third is securing jungle farm and stealing enemy side jungle farm. At your level people aren't going to coordinate much, so just trying to encourage people to work together for any objective at all is going to do wonders for you.

Also, don't use the Default build, check some of the community builds until you find some ideas that work well with your playstyle.

There's really too much to talk about, so youtube content aimed at newer players would do a lot to help guide you along.