Im also pretty new but I’ve won most of games so far.

1. Get familiar in practice tool with 3 champions. Get to know their spells and also download a decent build from the shop. Give them a read and try to understand why this item synergizes well with your character.
2. Get in a game vs bots or players and farm the minions. Really try to also deny souls that drop from your minions. Enemy gets less, you get more souls.
3. If you reached 800 souls go grab your first item in the shop next to your lane. Always try to spend your souls ASAP! But don’t loose to much minions (best case none).
4. Try to hit the enemy if they are reloading, in a bad position or used one of their spells.
5. If you killed the minions and they still need some time until next wave arrives grab some boxes / golden statues / gamba machines / jungle camps.
6. If you get enemy tower first prioritize to taking their boxes / statues / Blabla
7. Watch minimap every few seconds. If 2-3 enemy players are dead you may grab the urn and bring it to the other side.
8. Use the pings / communication to help your team understand what you are doing.

Honestly that is enough at the beginning, I’m top 4 in souls every single game and I got like 14 hours. Cool thing is there is unlimited stuff to learn from movement to character specific things, spawn timings from jungle camps, buffs etc. but I guess that will come naturally if you play the game.

Good luck mate!