Setup and Key Actions for Hanumanasana
From uttanasana (standing forward bend), step your left leg back into a lunge, and lower your back knee to the floor. Shift your hips back so that they're stacked directly over your back knee. Walk your front foot forward (so that your front leg is relatively straight), and peel the sole of your foot up off the floor so that only your front heel remains on the mat and your front foot is flexed. Come up onto your fingertips. You may discover that you're able to find more length through your spine if you place blocks underneath your fingertips. Dig your front heel into your mat, and "micro-bend" your front knee. Now bring your hand to touch your inner quadricep, above your inner knee. Can you feel the muscle firm under your fingers? If not, try bending your front knee a little more, then slowly straightening your leg (without locking). If you're more verbally oriented, you might also find the cue "Lift your inner knee" to be useful here.
Maintain that activation, and press your fingertips into the floor/blocks. Draw the pinky-toe side of your right foot back toward you (it will tend to drop forward), and press forward through the ball of your right big toe (it will tend to drop back).
In the beginning, keep your back toes tucked under (back knee on the floor). In this pose, there's a common tendency to let the torso turn toward the back leg and to collapse into the front hip. To counter this, draw the left side (back-leg side) of your belly toward the right side (front-leg side) of your belly to square your torso to the top of your mat, and lift your back inner thigh up.
Lift up through your low belly and stretch out through both of your legs, keeping them active and engaged as you lower your pelvis closer to the floor.
If you're able to maintain the inner rotation of the back leg that keeps the torso relatively "square" to the front of the mat, you can point your back foot so that the top of the foot rests on the mat. You could also play with extending your arms up to the sky. If you start to roll onto your right hip or otherwise lose stability in the pose, tuck your back toes again and press your fingertips into the floor.
To exit the pose, press into your fingertips, draw back up to a lunge, and change sides.
Try placing a block underneath your front thigh. If you find you could use a little more height, try stacking two or three blocks. Place two additional blocks underneath your fingertips (the height of the blocks under your hands will vary, depending on the height of the blocks under your front thigh).
Over time, you might find that you can remove a block from your stack, bring your block to a lower height, or omit it altogether so that you can descend closer to the floor.