Everyone starts with tight hamstrings, welcome to the club
How long do you sit in poses? The best beginner advice to hamstrings I can give is to do legs up the wall for a MINIMUM of five minutes a day every day of the year (if possible).
Read up on yin yoga. Unlike the trendy "boutique” yoga studios where they race from pose to pose...to give you that sweaty, "go for the burn" alternative to SoulCycle, a slow, pensive practice where you stay in each pose for a few minutes will help your body open up and relax.
Make sure your back is a straight as possible. The goal isn’t to touch your toes, it’s to bend at hips with a straight back. If you only go forward a little bit...great! Celebrate that. Bend your knees and stay there for minutes at a time. The straighter your back, the more you will feel it in your hamstrings
If it’s in the budget, attend classes or take a private lesson to learn the best way to work with your body's limitations
See the third tip in my signature for tips on hamstrings.