Yoga will definitely help with your lifts. It can be excellent for your off days of training to have longer yoga sessions (maybe go to a class at your gym?). I started doing Yoga with Adrienne (YouTube) in the mornings and find it really helps loosen me up and start my day with some nice intention.
Fitness
I love Yoga with Adrienne. She videos can either be difficult or easy but they all relax me and loosen me up. I highly recommend her videos.
Either do yoga vs. weightlifting on different days, or do yoga after. You don't want to do static stretching before weight lifting, just dynamic stretching. But yoga (or any form of dynamic stretching) after weightlifting does feel nice.
I personally like to do it first thing in the mornings on my rest days. It works mostly but can be a little tough if my chest or arms in particular are sore.
I would say just do it whenever you can work it into your day. As long as it's not directly before your actual workout, otherwise you'll risk injury.
Do you follow a video or something, or do you get used to the poses and know what to do?
I found the calisthenics people have decent ratio between flexibility and strength.
Have been following this guy on and off for months. He also has other 15 min to 1hr videos for yoga/flexibility/strength which have a decent progression level.
Here is an alternative Piped link(s):
https://www.piped.video/watch?v=N37Y47B2FTo&t=0
Piped is a privacy-respecting open-source alternative frontend to YouTube.
I'm open-source; check me out at GitHub.
I follow YouTube videos for flows at home. There are a bunch of options depending on your skill level, time, and type of yoga to choose from. If you're brand new I would say to not do a flow more than 30 minutes and make sure the video is geared for beginners or else you'll end up trying to do a headstand or half-moon before you're ready. When I was starting out I personally found 'Yoga with Kassandra' to be the best for me in terms of learning.
Yoga seems to help a lot with my lower back/hamstrings, which seem to just get less and less mobile over time as I squat and deadlift. I should really do yoga more, but at the moment I only do it when my back gets so tight that it interferes with my everyday mobility.
Not yoga specifically , but I did the McGill Big 3 (look up the video from Squat University). I'd do it every morning, slowly increasing the difficulty of each movement.
I do powerlifting so core strength and stability is super beneficial to avoid injuries.
Start with kettlebell turkish get ups.