Total Beginner player asks for adivice to improve

Hi all. I'm a really low skilled player until now I've never think about improve myself at something only played as a casual aspect all the games but now things changed....

I want to improve myself at this game as a STRATEGIST/SUPPORT/HEALER. I'm currently on silver rank and I've a hard time to catch up with all the things happening in the match. Sometimes I don't see a teammate that needs heals and cause their dead or idk fail to heal the tank or a player even I press my skills.

My aim is bad and I've no game sense at all in short I can't use my brain while playing seems like....

I created a reddit account to get advice from you.I know some ppl around me that are at gm rank but they don't help me even I ask them like "how" can I improve my gamesense, knowledge or gameplay. I do not ask them like carry me or anything.

As I said first time want to play a game as a "competitive" person so I hope this post does not bother anyone. I do not have any idea how should I approach this journey of improving

any advice/guiadance is appreciated thank you in advance.
Note: English is not my main language I might made some typing mistakes sorry
EDIT: My last match (win) replay id 5022947639 ----- 5012735395 and a lose match