I can't find the constraints on the right hand of side of figma and also where i can choose the fill container option

Hey there,
Thanks for sharing your screenshot! This looks odd, you should be able to see the constraint feature in the design panel. Would you be able to share a copy of your file so we can have a better look at it?
If you are hesitant to share publicly, you can reach out directly to the support with a copy of your file: here (please invite support-share@figma.com to the file with “can edit” permissions so we can take a further look. Please note this will not count towards your billing.)

As a reminder, here’s guide how to use constraint: https://help.figma.com/hc/en-us/articles/360039957734-Apply-constraints-to-define-how-layers-resize#apply

About the fill container, you’ll need to click on the child object (not the parent frame) to be able to select “Fill container”.

Hope this helps!