Ive never touched mouse and keyboard before, any tips?

I recently got a mouse and keyboard for my ps5 so I can use it to play overwatch. Like the title says I've never played a game with this set up before. I have always been a console player my entire life and I've held a controller ever since I learned how to walk. I have 1000 hours on overwatch and have peaked in masters but when I started playing today with mouse and keyboard it was like i was learning to walk again. It looks like I've never played the game before and it's very hard. So im here to ask if people have any tips or video guides on 1 how to use a mouse and keyboard ie best finger placements, hand positions, posture etc. And 2 if there are any guides or custom maps for improvement movement and aiming for mouse and keyboard. Thanks yall!