This looks like a pants size chart for American guests. The unit of measurement is inches:
According to the order you provided, the translation contents are as follows.
Waist slack (@ topedge) 19 1/2 Waist slack measurement (along the fixed edge)
Waist slack (@ btmiedge) 2 1 waist slack measurement (along the bottom edge)
Belt height 1 5/8 waist height (waist width)
Position of high hip circumference (top edge of Frm) 4 Position of high hip circumference (measured downward from the fixed edge of waist)
High hip girth 23 High hip girth size
Position of low hip circumference (upper edge of Frm) 8 Position of low hip circumference (measured downward from upper edge of waist).
Low hip circumference 24 1/2 low hip circumference
Curtain/Length (frm top edge) 6 3/8 Length of the placket (measured downward from the waist top edge)
Zipper opening 3 front 3/4 front zipper opening length (not shown, uncertain)
Zipper length 4 1/2 zipper length
Protrusion (front top edge) 10 3/4 front wavelength (front crotch length, from the top edge of waist)
Back rise (frm top edge) 18 1/2 back wave length (back crotch bending length, from waist top)
Saddle @ 2" 9 has no picture material and cannot be translated accurately.
Hip level/depth (frm top edge) 10 1/2 Hip low position (leg root position) is away from the top edge.
Thigh (@ widest) 15 1/4 Leg root circumference (thickest part)
Mid-thickness position (from crotch @ seam) 6 3/4 Mid-leg circumference (low crotch, downward along seam)
Medium thickness 12 3/4 Mid-leg circumference
Knee position (from crotch @ seam) 13 1/2 knee circumference (from crotch down along seam)
Knee 10 3/4 knee circumference
Legopening 1 1 foot circumference
Internal seam length of internal seam 33
I hope the above translation is helpful to you. If you can have the guest's graphic information, you will get more accurate and detailed Chinese meaning. thank you