I typically like playing unranked, but (as a solo player) it's the parties that drove me over the edge. Only ranked has strict-solo matchmaking, so here I am.
So many games I would be matched with a 3-4 stack who doesn't say anything or mark the map, wait for me to mark safe lane and pick CM or something and then picks two supports....
Like, it's unranked so have fun, but in those games it's like a 5% chance to win. Not very fun for either team.
Dota is the game where you need to understand everything is revolved around position and timing, just like soccer/football and basketball.
Play with Bot first as cores, then try to avoid enemy and farming items, then do pickoff one enemy. Then, learn how to play as support; understand ward, dust, smoke, rune timings; then try to support your unranked games to understand gameflow better.